GM Full-Size Trucks 1970-1979 Repair Guide

Transmission Assembly

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REMOVAL & INSTALLATION



See Figures 1 and 2



Click image to see an enlarged view

Fig. Fig. 1: Transfer case linkage - 205 series shown



Click image to see an enlarged view

Fig. Fig. 2: Transfer case mounting - 205 series shown

2-Wheel Drive Models
  1. Jack up your vehicle and support it with jackstands.
  2.  
  3. Drain the transmission.
  4.  
  5. Disconnect the speedometer cable, and back-up lamp wire at transmission.
  6.  
  7. Disconnect the shift control lever or shift control from the transmission. On 4-speeds, remove the gearshift lever by pressing down firmly on the slotted collar plate with a pair of channel lock pliers and rotating counterclockwise. Plug the opening to keep out dirt.
  8.  
  9. Remove driveshaft after making the position of the shaft to the flange.
  10.  
  11. Position a transmission jack or its equivalent under the transmission to support it.
  12.  
  13. Remove the crossmember. Visually inspect to see if other equipment, brackets or lines, must be removed to permit removal of transmission.
  14.  

Mark position of crossmember when removing to prevent incorrect installation. The tapered surface should face the rear.

  1. Remove the flywheel housing underpan.
  2.  
  3. Remove the top two transmission-to-housing bolts and insert two guide pins.
  4.  

The use of guide pins will not only support the transmission but will prevent damage to the clutch disc. Guide pins can be made by taking two bolts, the same as those just removed only longer, and cutting off the heads. Slot the ends for a screwdriver. Be sure to support the clutch release bearing and support assembly during removal of the transmission. This will prevent the release from falling out of the flywheel housing.

  1. Remove two remaining bolts and slide transmission straight back from engine. Use care to keep the transmission drive gear straight in line with clutch disc hub.
  2.  
  3. Remove the transmission from beneath your vehicle.
  4.  
  5. When installing, tighten the mounting bolts to 55 ft. lbs. (75 Nm) for vehicles through 1972, or to 75 ft. lbs. (102 Nm) for 1973-79 vehicles.
  6.  
  7. Place transmission in gear and rotate transmission flange or output yoke to aid entry of main drive gear into disc's splines. Make sure clutch release bearing is in position.
  8.  


WARNING
Do not force the transmission into the clutch disc hub. Do not let the transmission hang unsupported in the splined portion of the clutch disc.

4-Wheel Drive Models
3-SPEED
  1. Jack up the vehicle and support it on jackstands. Remove the skid plate, if so equipped.
  2.  
  3. Drain the transmission and transfer case. Remove the speedometer cable and the TCS switch, if so equipped, from the side of the transmission.
  4.  
  5. Disconnect the driveshafts and secure them out of the way.
  6.  
  7. Remove the shifter lever by removing the pivot bolt to the adapter assembly. You can then push the shifter up out of the way.
  8.  
  9. On 1978 and later models, remove the bolts attaching the strut to the right side of the transfer case and the rear of the engine, and remove the strut.
  10.  
  11. While supporting the transfer case, remove the attaching bolts to the adapter.
  12.  
  13. Remove the transfer case securing bolts from the frame and lower and remove the transfer case. The case is attached to the right side of the frame.
  14.  
  15. Disconnect the shift rods from the transmission.
  16.  
  17. While holding the rear of the engine with a jack, remove the adapter mounting bolts.
  18.  
  19. Remove the upper transmission bolts and insert two guide pins to keep the assembly aligned.
  20.  
  21. Remove the flywheel pan and the lower transmission bolts.
  22.  
  23. Pull the transmission and the adapter straight back on the guide pins until the input shaft is free of the clutch disc.
  24.  
  25. The transmission and the adapter are removed as on assembly. The adapter can be separated once the assembly is out.
  26.  
  27. When installing, place the transmission in gear and turn the output shaft to align the clutch splines. Transmission bolt torque is 55 ft. lbs. (75 Nm) for vehicles through 1972, and 75 ft. lbs. (102 Nm) for 1973-79 vehicles. See Transfer Case installation for adapter bolt tightening specifications.
  28.  

4-SPEED
  1. Remove the shifter boots and retainers.
  2.  
  3. Remove the transmission shift lever. See the two wheel drive procedure for details on removing the lever. It may be necessary to remove the center floor outlet from the heater to complete the next step. Remove the center console, if so equipped.
  4.  
  5. Remove the transmission cover after releasing the attaching screws. It will be necessary to rotate the cover 90 degrees to clear the transfer case shift lever.
  6.  
  7. Disconnect the transfer case shift lever link assembly and the lever from the adapter. Remove the skid plate, if any.
  8.  
  9. Remove the back-up light, the TCS switch, and the speedometer cable from the transmission.
  10.  
  11. Raise and support the truck with jackstands. Support the engine. Drain the transmission and the transfer case. Detach both driveshafts and secure them out of the way.
  12.  
  13. Remove the transmission-to-frame bolts. To do this, it will be necessary to open the locking tabs. Remove the transfer case-to-frame bracket bolts.
  14.  
  15. While supporting the transmission and transfer case, remove the crossmember bolts and the crossmember. It will be necessary to rotate the crossmember to remove it from the frame.
  16.  
  17. Remove the lower clutch housing cover.
  18.  

On V8 engines it is necessary to remove the exhaust crossover pipe.

  1. Remove the transmission-to-clutch housing bolts. Remove the upper bolts first and install guide pins.
  2.  
  3. Slide the transmission back until the input shaft clears the clutch assembly and then lower the unit.
  4.  
  5. The transfer case and transmission is installed as an assembly. Put the transmission in gear and turn the output shaft to align the clutch splines. Tighten the transmission bolts to 55 ft. lbs. (75 Nm) for vehicles through 1972, or to 75 ft. lbs. (102 Nm) for 1973-79 vehicles.
  6.  

OVERHAUL



Saginaw 3-Speed (76mm)

See Figure 3



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of the Saginaw 3-speed manual transmission

TRANSMISSION CASE DISASSEMBLY
  1. Remove the side cover assembly and the shift forks.
  2.  
  3. Remove the clutch gear bearing retainer.
  4.  
  5. Remove the clutch gear bearing-to-gear stem snapring. Pull the clutch gear outward until a screwdriver can be inserted between the bearing and the case. Remove the clutch gear bearing.
  6.  
  7. Remove the speedometer driven gear and the extension bolts.
  8.  
  9. Remove the Reverse idler shaft snapring.
  10.  
  11. Remove the mainshaft and the extension assembly through the rear of the case.
  12.  
  13. Remove the clutch gear and the 3rd speed blocking ring from inside the case. Remove the 14 roller bearings from the clutch gear.
  14.  
  15. Expand the snapring which retains the mainshaft rear bearing and remove the extension.
  16.  
  17. Using a dummy shaft, drive the countershaft and the key out through the rear of the case. Remove the gear, the two tanged thrust washers and the dummy shaft. Remove the bearing washer and the 27 roller bearings from each end of the countergear.
  18.  
  19. Using a long drift, drive the Reverse idler shaft and key through the rear of the case.
  20.  
  21. Remove the Reverse idler gear and the tanged steel thrust washer.
  22.  

TRANSMISSION CASE ASSEMBLY
  1. Using a dummy shaft, grease and load a row of 27 roller bearings and a thrust washer at each end of countergear.
  2.  
  3. Place the countergear assembly into the case from the rear. Place a tanged thrust washer (tang away from the gear) at each end. Install the countershaft and the key, making sure that the tangs align with the notches in the case.
  4.  
  5. Install the Reverse idler gear thrust washer, the gear and the shaft with a key from the rear of the case.
  6.  

Be sure the thrust washer is between the gear and the rear of the case with the tang toward the notch in the case.

  1. Expand the snapring in the extension housing. Assemble the extension over the rear of the mainshaft and onto the rear bearing. Seat the snapring in the rear bearing groove.
  2.  
  3. Install the 14 mainshaft pilot bearings into the clutch gear cavity. Assemble the 3rd speed blocking ring onto the clutch gear clutching surface with the teeth toward the gear.
  4.  
  5. Place the clutch gear, the pilot bearings and the 3rd speed blocking ring assembly over the front of the mainshaft assembly; be sure the blocking rings align with the keys in the 2nd/3rd synchronizer assembly.
  6.  
  7. Stick the extension gasket to the case with grease. Install the clutch gear, the mainshaft and the extension together; be sure the clutch gear engages the teeth of the countergear anti lash plate. Tighten the extension bolts to 45 ft. lbs. (61 Nm).
  8.  
  9. Place the bearing over the stem of the clutch gear and into the front case bore. Install the front bearing to the clutch gear snapring.
  10.  
  11. Install the clutch gear bearing retainer and the gasket. The retainer oil return hole must be at the bottom. Tighten the retainer bolts to 10 ft. lbs. (13.5 Nm).
  12.  
  13. Install the Reverse idler gear shaft E-ring.
  14.  
  15. Shift the synchronizer sleeves to the Neutral positions. Install the cover, the gasket and the forks; aligning the forks with the synchronizer sleeve grooves. Tighten the side cover bolts to 10 ft. lbs. (13.5 Nm).
  16.  
  17. Install the speedometer driven gear.
  18.  

MAINSHAFT DISASSEMBLY
  1. Remove the 2nd/3rd speed sliding clutch hub snapring from the mainshaft. Remove the clutch assembly, the 2nd speed blocking ring and the 2nd gear from front of the mainshaft.
  2.  
  3. Depress the speedometer drive gear retaining clip and remove the gear. Some units have a metal speedometer driver gear which must be pulled off.
  4.  
  5. Remove the rear bearing snapring.
  6.  
  7. Support the Reverse gear and press on the rear of the mainshaft. Remove the Reverse gear, the thrust washer, the spring washer, the rear bearing and the snapring.
  8.  

When pressing off the rear bearing, be careful not to cock the bearing on the shaft.

  1. Remove the 1st and Reverse sliding clutch hub snapring. Remove the clutch assembly, 1st speed blocking ring and the 1st gear; sometimes the synchronizer hub and gear must be pressed off.
  2.  

MAINSHAFT ASSEMBLY
  1. Turn the front of the mainshaft up.
  2.  
  3. Install the 2nd gear with the clutching teeth up; the rear face of the gear butts against the flange on the mainshaft.
  4.  
  5. Install a blocking ring with the clutching teeth down. The three blocking rings are the same.
  6.  
  7. Install the 2nd/3rd speed synchronizer assembly with the fork slot down; press it onto the mainshaft splines.
  8.  

Both synchronizer assemblies are the same. Be sure that the blocking ring notches align with the synchronizer assembly keys.

  1. Install the synchronizer snapring; both synchronizer snaprings are the same.
  2.  
  3. Turn the rear of the shaft up, then install the 1st gear with the clutching teeth up; the front face of the gear butts against the flange on the mainshaft.
  4.  
  5. Install a blocking ring with the clutching teeth down.
  6.  
  7. Install the 1st/Reverse synchronizer assembly with the fork slot down, then press it onto the mainshaft splines; be sure the blocking ring notches align with the synchronizer assembly keys.
  8.  
  9. Install the snapring.
  10.  
  11. Install the Reverse gear with the clutching teeth down.
  12.  
  13. Install the steel Reverse gear thrust washer and the spring washer.
  14.  
  15. Press the rear ball bearing onto the shaft with the snapring slot down.
  16.  
  17. Install the snapring.
  18.  
  19. Install the speedometer drive gear and the retaining clip; press on the metal speedometer drive gear.
  20.  

CLUTCH KEYS AND SPRINGS REPLACEMENT

The keys and the springs may be replaced if worn or broken, but the hubs and sleeves are matched pairs, they must be kept together.

  1. Mark the hub and sleeve for reassembly.
  2.  
  3. Push the hub from the sleeve, then remove the keys and the springs.
  4.  
  5. Place the three keys and the two springs (one on each side of hub) in position, so the three keys are engaged by both springs; the tanged ends of the springs should not be installed into the same key.
  6.  
  7. Slide the sleeve onto the hub by aligning the marks.
  8.  

A groove around the outside of the synchronizer hub marks the end that must be opposite the fork slot in the sleeve when assembled.

EXTENSION OIL SEAL AND BUSHING REPLACEMENT
  1. Remove the seal.
  2.  
  3. Using the bushing removal and installation tool, drive the bushing into the extension housing.
  4.  
  5. Drive the new bushing in from the rear. Lubricate the inside of the bushing and the seal. Install a new oil seal with the extension seal installation tool or other suitable tool.
  6.  

CLUTCH BEARING RETAINER OIL SEAL REPLACEMENT
  1. Pry the old seal out.
  2.  
  3. Install the new seal using the seal installer. Seat the seal in the bore.
  4.  

Muncie 3-Speed (83mm)

See Figure 4



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of the Muncie 3-speed (83mm) manual transmission

TRANSMISSION UNIT DISASSEMBLY
  1. Remove side cover and shift forks.
  2.  
  3. Unbolt extension and rotate to line up groove in extension flange with reverse idler shaft. Drive reverse idler shaft and key out of case with a brass drift.
  4.  
  5. Move 2nd/3rd synchronizer sleeve forward. Remove extension housing and mainshaft assembly.
  6.  
  7. Remove reverse idler gear from case.
  8.  
  9. Remove 3rd speed blocker ring from clutch gear.
  10.  
  11. Expand snapring which holds mainshaft rear bearing. Tap gently on end of mainshaft to remove extension.
  12.  
  13. Remove clutch gear bearing retainer and gasket.
  14.  
  15. Remove snapring. Remove clutch gear from inside case by gently tapping on end of clutch gear.
  16.  
  17. Remove oil slinger and 16 mainshaft pilot bearings from clutch gear cavity.
  18.  
  19. Slip clutch gear bearing out front of case. Aid removal with a screwdriver between case and bearing outer snapring.
  20.  
  21. Drive countershaft and key out to rear.
  22.  
  23. Remove countergear and two tanged thrust washers.
  24.  

MAINSHAFT DISASSEMBLY
  1. Remove speedometer drive gear. Some speedometer drive gears, made of metal, must be pulled off.
  2.  
  3. Remove rear bearing snapring.
  4.  
  5. Support reverse gear. Press on rear of mainshaft to remove reverse gear, thrust washer and rear bearing. Be careful not to cock the bearing on the shaft.
  6.  
  7. Remove 1st and reverse sliding clutch hub snapring.
  8.  
  9. Support 1st gear. Press on rear of mainshaft to remove clutch assembly, blocker ring and 1st gear.
  10.  
  11. Remove 2nd and 3rd speed sliding clutch hub snapring.
  12.  
  13. Support 2nd gear. Press on front of mainshaft to remove clutch assembly, 2nd speed blocker ring and 2nd gear from shaft.
  14.  

CLUTCH KEYS AND SPRINGS REPLACEMENT

Keys and springs may be replaced if worn or broken, but the hubs and sleeves must be kept together as originally assembled.

  1. Mark hub and sleeve for reassembly.
  2.  
  3. Push hub from sleeve. Remove keys and springs.
  4.  
  5. Place three keys and two springs, one on each side of hub, so all three keys are engaged by both springs. The tanged end of the springs should not be installed into the same key.
  6.  
  7. Slide the sleeve onto the hub, aligning the marks.
  8.  

EXTENSION OIL SEAL AND BUSHING REPLACEMENT
  1. Remove seal.
  2.  
  3. Using bushing remover and installer, or other suitable tool, drive bushing into extension housing.
  4.  
  5. Drive new bushing in from rear. Lubricate inside of bushing and seal. Install new oil seal with extension seal installer or suitable tool.
  6.  

CLUTCH BEARING RETAINER OIL SEAL REPLACEMENT
  1. Pry old seal out.
  2.  
  3. Install new seal using seal installer or suitable tool. Seat seal in bore.
  4.  

MAINSHAFT ASSEMBLY
  1. Lift front of mainshaft.
  2.  
  3. Install 2nd gear with clutching teeth up; the rear face of the gear butts against the mainshaft flange.
  4.  
  5. Install a blocking ring with clutching teeth downward. All three blocking rings are the same.
  6.  
  7. Install 2nd and 3rd synchronizer assembly with fork slot down. Press it onto mainshaft splines. Both synchronizer assemblies are identical but are assembled differently. The 2nd/3rd speed hub and sleeve is assembled with the sleeve fork slot toward the thrust face of the hub; the 1st/reverse hub and sleeve, with the fork slot opposite the thrust face. Be sure that the blocker ring notches align with the synchronizer assembly keys.
  8.  
  9. Install synchronizer snapring. Both synchronizer snaprings are the same.
  10.  
  11. Turn rear of shaft up.
  12.  
  13. Install 1st gear with clutching teeth upward; the front face of the gear butts against the flange on the mainshaft.
  14.  
  15. Install a blocker ring with clutching teeth down.
  16.  
  17. Install 1st and reverse synchronizer assembly with fork slot down. Press it onto mainshaft splines. Be sure blocker ring notches align with synchronizer assembly keys and synchronizer sleeves face front of mainshaft.
  18.  
  19. Install snapring.
  20.  
  21. Install reverse gear with clutching teeth down.
  22.  
  23. Install steel reverse gear thrust washer with flats aligned.
  24.  
  25. Press rear ball bearing onto shaft with snapring slot down.
  26.  
  27. Install snapring.
  28.  
  29. Install speedometer drive gear and retaining clip.
  30.  

TRANSMISSION UNIT ASSEMBLY
  1. Place a row of 29 roller bearings, a bearing washer, a second row of 29 bearings and a 2nd bearing washer at each end of the countergear. Hold in place with grease.
  2.  
  3. Place countergear assembly through rear case opening with a tanged thrust washer, tang away from gear, at each end. Install countershaft and key from rear of case. Be sure that thrust washer tangs are aligned with notches in case.
  4.  
  5. Place reverse idler gear in case. Do not install reverse idler shaft yet. The reverse idler gear bushing may not be replaced separately, it must be replaced as a unit.
  6.  
  7. Expand snapring in extension. Assemble extension over mainshaft and onto rear bearing. Seat snap ring.
  8.  
  9. Load 16 mainshaft pilot bearings into clutch gear cavity. Assemble 3rd speed blocker ring onto clutch gear clutching surface with teeth toward gear.
  10.  
  11. Place clutch gear assembly, without front bearing, over front of mainshaft. Make sure that blocker ring notches align with keys in 2nd/3rd synchronizer assembly.
  12.  
  13. Stick gasket onto extension housing with grease. Assemble clutch gear, mainshaft and extension to case together. Make sure that clutch gear teeth engage teeth of countergear anti-lash plate.
  14.  
  15. Rotate extension housing. Install reverse idler shaft and key.
  16.  
  17. Tighten the extension bolts to 45 ft. lbs. (61 Nm).
  18.  
  19. Install oil slinger with inner lip facing forward. Install front bearing outer snapring and slide bearing into case bore.
  20.  
  21. Install snapring to clutch gear stem. Install bearing retainer and gasket and tighten to 20 ft. lbs. (27 Nm). The retainer oil return hole must be at 6 o'clock.
  22.  
  23. Shift both synchronizer sleeves to neutral positions. Install side cover, inserting shifter forks in synchronizer sleeve grooves.
  24.  
  25. Tighten the side cover bolts to 20 ft. lbs. (27 Nm).
  26.  

Tremec 3-Speed

See Figure 5



Click image to see an enlarged view

Fig. Fig. 5: Exploded view of the Tremec 3-speed manual transmission

TRANSMISSION DISASSEMBLY
  1. Drain the lubricant by removing the lower extension housing bolt.
  2.  
  3. Remove the case cover and gasket.
  4.  
  5. Remove the long spring that holds the detent plug in the case and remove the detent plug with a small magnet.
  6.  
  7. Remove the extension housing and gasket.
  8.  
  9. Remove the front bearing retainer and gasket.
  10.  
  11. Remove the filler plug on the right side of the transmission case. Working through the plug opening, drive the roll pin out of the case and countershaft with a 1 / 4 in. (6mm) punch.
  12.  
  13. Hold the countershaft gear with a hook. Install dummy shaft and push the countershaft out of the rear of the case. As the countershaft comes out, lower the gear cluster to the bottom of the case. Remove the countershaft.
  14.  
  15. Remove the snapring that holds the speedometer drive gear on the output shaft. Slip the gear off the shaft and remove the gear lock ball.
  16.  
  17. Remove the snapring that holds the output shaft bearing. Using a special bearing puller, remove the output shaft bearing.
  18.  
  19. Place both shift levers in the neutral (center) position.
  20.  
  21. Remove the set screw that holds the 1st/reverse shift fork to the shift rail. Slip the 1st/reverse shift rail out through the rear of the case.
  22.  
  23. Move the 1st/reverse synchronizer forward as far as possible. Rotate the 1st/reverse shift fork upwards and lift it out of the case.
  24.  
  25. Place the 2nd/3rd shift fork in the 2nd position. Remove the set screw. Rotate the shift rail 90 degrees.
  26.  
  27. Lift the interlock plug out of the case with a magnet.
  28.  
  29. Remove the expansion plug from the 2nd/3rd shift rail by lightly tapping the end of the rail. Remove the 2nd/3rd shift rail.
  30.  
  31. Remove the 2nd/3rd shift rail detent plug and spring from detent bore.
  32.  
  33. Remove the input gear and shaft from the case.
  34.  
  35. Rotate the 2nd/3rd shift fork upwards and remove from case.
  36.  
  37. Using caution, lift the output shaft assembly out through top of case.
  38.  
  39. Lift the reverse idler gear and thrust washers out of case. Remove the countershaft gear, thrust washer and dummy shaft from case.
  40.  
  41. Remove the snapring from the front of the output shaft. Slip the synchronizer and 2nd gear off shaft.
  42.  
  43. Remove the 2nd snapring from output shaft and remove the thrust washer, 1st gear and blocking ring.
  44.  
  45. Remove the 3rd snapring from the output shaft. The 1st/reverse synchronizer hub is a press fit on the output shaft. Remove the synchronizer hub with an arbor press.
  46.  


WARNING
Do not attempt to remove or install the synchronizer hub by prying or hammering.

SHIFT LEVERS AND SEALS
  1. Remove shift levers from the shafts. Slip the levers out of case. Discard shaft sealing O-rings.
  2.  
  3. Lubricate and install new O-rings on shift shafts.
  4.  
  5. Install the shift shafts in the case and secure shift levers.
  6.  

INPUT SHAFT BEARINGS
  1. Remove the snapring securing the input shaft bearing. Using an arbor press, remove the bearing.
  2.  
  3. Press the input shaft bearing onto shaft using correct tool.
  4.  

SYNCHRONIZERS
  1. Scribe alignment marks on synchronizer hubs before disassembly. Remove each synchronizer hub from the synchronizer sleeves.
  2.  
  3. Separate the inserts and insert springs from the hubs.
  4.  


WARNING
Do not mix parts from the separate synchronizer assemblies.

  1. Install the insert spring in the hub of the 1st/reverse synchronizer. Be sure that the spring covers all the insert grooves. Start the hub on the sleeve making certain that the scribed marks are properly aligned. Place the 3 inserts in the hub, small ends on the inside. Slide the sleeve and reverse gear onto hub.
  2.  
  3. Install 1 insert spring into a groove on the 2nd/3rd synchronizer hub. Be sure that all 3 insert slots are covered. Align the scribed marks on the hub and sleeve and start the hub into the sleeve. Position the 3 inserts on the top of the retaining spring and push the assembly together. Install the remaining retainer spring so that the spring ends cover the same slots as the 1st spring. Do not stagger the springs. Place a synchronizer blocking ring on the ends of the synchronizer sleeve.
  4.  

COUNTERSHAFT GEAR BEARINGS
  1. Remove the dummy shaft, needle bearings and bearing retainers from the countershaft gear.
  2.  
  3. Coat the bore in each end of the countershaft gear with grease.
  4.  
  5. Hold the dummy shaft in the gear and install the needle bearings in the case.
  6.  
  7. Place the countershaft gear, dummy shaft, and needle bearings in the case.
  8.  
  9. Place the case in a vertical position. Align the gear bore and the thrust washers with the bores in the case and install the countershaft.
  10.  
  11. Place the case in a horizontal position. Check the countershaft gear end-play with a feeler gauge. Clearance should be between 0.004-0.018 in. (0.10-0.45mm). If clearance does not come within specifications, replace the thrust washers.
  12.  
  13. Install the dummy shaft in the countershaft gear and leave the gear at the bottom of the transmission case.
  14.  

TRANSMISSION ASSEMBLY
  1. Cover the reverse idler gear thrust surfaces in the case with a thin film of lubricant, and install the 2 thrust washers in the case.
  2.  
  3. Install the reverse idler gear and shaft in the case. Align the case bore and thrust washers with gear bore and install the reverse idler shaft.
  4.  
  5. Measure the reverse idler gear end-play with a feeler gauge. Clearance should be between 0.004-0.018 in. (0.10-0.45mm). If end-play is not within specifications, replace the thrust washers. If clearance is correct, leave the reverse idler gear in case.
  6.  
  7. Lubricate the output shaft splines and machined surfaces with transmission oil.
  8.  
  9. The 1st/reverse synchronizer hub is a press fit on the output shaft. Hub must be installed in an arbor press. Install the synchronizer hub with the teeth end of the gear facing towards the rear of the shaft.
  10.  


WARNING
Do not attempt to install the 1st/reverse synchronizer with a hammer.

  1. Place the blocking ring on the tapered surface of the 1st gear.
  2.  
  3. Slide the 1st gear on the output shaft with the blocking ring toward the rear of the shaft. Rotate the gear as necessary to engage the 3 notches in the blocking ring with the synchronizer inserts. Install the thrust washer and snapring.
  4.  
  5. Slide the blocking ring onto the tapered surface of the 2nd gear. Slide the 2nd gear with blocking ring and the 2nd/3rd synchronizer on the mainshaft. Be sure that the tapered surface of 2nd gear is facing the front of the shaft and that the notches in the blocking ring engage the synchronizer inserts. Install the snapring and secure assembly.
  6.  
  7. Cover the core of the input shaft with a thin coat of grease.
  8.  


WARNING
A thick film of grease will plug lubricant holes and cause damage to bearings.

  1. Install bearings. Install the input shaft through the front of the case and insert snapring in the bearing groove.
  2.  
  3. Install the output shaft assembly in the case. Position the 2nd/3rd shift fork on the 2nd/3rd synchronizer.
  4.  
  5. Place a detent plug spring and a plug in the case. Place the 2nd/3rd synchronizer in the 2nd gear position (toward the rear of the case). Align the fork and install the 2nd/3rd shift rail. It will be necessary to depress the detent plug to install the shift rail in the bore. Move the rail forward until the detent plug enters the forward notch (2nd gear).
  6.  
  7. Secure the fork to the shift rail with a set screw and place the synchronizer in neutral.
  8.  
  9. Install the interlock plug in the case.
  10.  
  11. Place the 1st/reverse synchronizer in the 1st gear position (towards the front of the case). Place the shift fork in the groove of the synchronizer. Rotate the fork into position and install the shift rail. Move the shift rail inward until the center notch (neutral) is aligned with the detent bore. Secure shift fork with set screw.
  12.  
  13. Install a new shift rail expansion plug in the front of the case.
  14.  
  15. Hold the input shaft and blocking ring in position and move the output shaft forward to seat the pilot in the roller bearings on the input gear.
  16.  
  17. Tap the input gear bearing into place while holding the output shaft. Install the front bearing retainer and gasket. Tighten the attaching bolts to specifications.
  18.  
  19. Install the large snapring on the rear bearing. Place the bearing on the output shaft with the snapring end toward the rear of the shaft. Press the bearing into place using a special tool. Secure the bearing to the shaft with the snapring.
  20.  
  21. Hold the speedometer drive gear lock ball in the detent and slide the speedometer drive gear into position. Secure with snapring.
  22.  
  23. Place the transmission in the vertical position. Working with a screwdriver through the drain hole in the bottom of the case, align the bore of the countershaft gear and the thrust washer with the bore in the case.
  24.  
  25. Working from the rear of the case, push the dummy shaft out of the countershaft gear with the countershaft. Align the roll pin hole in the countershaft with the matching hole in the case. Drive the shaft into place and install the roll pin.
  26.  
  27. Position the new extension housing gasket on the case with sealer. Install the extension housing and tighten to specification.
  28.  
  29. Place the transmission in gear and pour gear oil over entire gear train while rotating the input shaft.
  30.  
  31. Install the remaining detent plug and long spring in case.
  32.  
  33. Position cover gasket on case with sealer and install cover. Tighten the cover bolts to specifications.
  34.  
  35. Check operation of transmission in all gear positions.
  36.  

Muncie 4-Speed (Top Cover)

See Figure 6



Click image to see an enlarged view

Fig. Fig. 6: Exploded view of the Muncie 4-speed (117mm) manual transmission - top cover type

TRANSMISSION UNIT
  1. Remove transmission cover assembly. Move reverse shifter fork so that reverse idler gear is partially engaged before attempting to remove cover. Forks must be positioned so rear edge of the slot in the reverse fork is in line with the front edge of the slot in the forward forks as viewed through tower opening.
  2.  
  3. Lock transmission into two gears. Remove the universal joint flange nut, universal joint front flange and brake drum assembly.
  4.  

On 4-wheel drive models, a special tool is needed to remove mainshaft rear locknut.

  1. Remove parking brake and brake flange plate assembly on those vehicles having a driveshaft parking brake.
  2.  
  3. Remove rear bearing retainer and gasket.
  4.  
  5. Slide speedometer drive gear off mainshaft.
  6.  
  7. Remove clutch gear bearing retainers and gasket.
  8.  
  9. Remove countergear front bearing cap and gasket.
  10.  
  11. Using a prybar, pry off countershaft front bearing.
  12.  
  13. Remove countergear rear bearing snaprings from shaft and bearing. Using special tool, remove countergear rear bearings.
  14.  
  15. Remove clutch gear bearing outer race to case retaining ring.
  16.  
  17. Remove clutch gear and bearing by tapping gently on bottom side of clutch gear shaft and prying directly opposite against the case and bearing snapring groove at the same time. Remove fourth gear synchronizer ring. Index cut out section of clutch gear in down position with countergear to obtain clearance for removing clutch gear.
  18.  
  19. Remove rear mainshaft bearing snapring and, using special tools, remove bearing from case. Slide 1st speed gear thrust washer off mainshaft.
  20.  
  21. Lift mainshaft assembly from case. Remove synchronizer cone from shaft.
  22.  
  23. Slide reverse idler gear rearward and move countergear rearward, then lift to remove from case.
  24.  
  25. To remove reverse idler gear, drive reverse idler gear shaft out of case from front to rear using a drift. Remove reverse idler gear from case.
  26.  

TRANSMISSION COVER DISASSEMBLY
  1. Remove shifter fork retaining pins and drive out expansion plugs. The third and fourth shifter fork must be removed before the reverse shifter head pin can be removed.
  2.  
  3. With shifter shafts in neutral position, remove shafts. Care should be taken when removing the detent balls and springs since removal of the shifter shafts will cause these parts to be forcibly ejected.
  4.  
  5. Remove retaining pin and drive out reverse shifter shaft.
  6.  

TRANSMISSION COVER ASSEMBLY
  1. In reassembling the cover, care should be taken to install the shifter shafts in order, reverse, 3rd/4th and 1st/2nd.
  2.  
  3. Place fork detent ball springs and balls in cover.
  4.  
  5. Start shifter shafts into cover and, while depressing the detent balls, push the shafts over the balls. Push reverse shaft through the yoke.
  6.  
  7. With the 3rd/4th shaft in neutral, line up the retaining holes in the fork and shaft. Detent balls should line up with detents in shaft.
  8.  
  9. After 1st and 2nd fork is installed, place two interlock balls between the low speed shifter shaft and the high speed shifter shaft in the crossbore of the front support boss. Grease the interlock pin and insert it in the 3rd/4th shifter shaft hole. Continue pushing this shaft through cover bore and fork until retainer hole in fork lines up with hole in shaft.
  10.  
  11. Place two interlock balls in crossbore in front support boss between reverse and 3rd and 4th shifter shaft. Then push remaining shaft through fork and cover bore, keeping both balls in position between shafts until retaining holes line up in fork and shaft. Install retaining pin.
  12.  
  13. Install 1st/2nd fork and reverse fork retaining pins. Install new shifter shaft hole expansion plugs.
  14.  

CLUTCH GEAR AND SHAFT ASSEMBLY
  1. Remove mainshaft pilot bearing rollers from clutch gear if not already removed and remove roller retainer. Do not remove snapring on inside of clutch gear.
  2.  
  3. Remove snapring securing bearing on steam of clutch gear.
  4.  
  5. To remove bearing, position a special tool to the bearing and, with an arbor press, press gear and shaft out of bearing.
  6.  

CLUTCH GEAR AND SHAFT ASSEMBLY
  1. Press bearing and new oil slinger onto clutch gear shaft using a special tool. Slinger should be located flush with bearing shoulder on clutch gear. Be careful not to distort oil slinger.
  2.  
  3. Install bearing snapring on clutch gear shaft.
  4.  
  5. Install bearing retainer ring in groove on O.D. of bearing. The bearing must turn freely on the shaft.
  6.  
  7. Install snapring on I.D. of mainshaft pilot bearing bore in clutch gear.
  8.  
  9. Lightly grease bearing surface in shaft recess, install transmission mainshaft pilot roller bearings and install roller bearing retainer. This roller bearing retainer holds bearings in position and, in final transmission assembly, is pushed forward into recess by mainshaft pilot.
  10.  

BEARING RETAINER OIL SEAL REPLACEMENT
  1. Remove retainer and oil seal assembly and gasket.
  2.  
  3. Pry out oil seal.
  4.  
  5. Install new seal with lip of seal toward flange of tool.
  6.  
  7. Support front surface of retainer in press and drive seal into retainer.
  8.  
  9. Install retainer and gasket on case.
  10.  

MAINSHAFT DISASSEMBLY
  1. Remove first speed gear.
  2.  
  3. Remove reverse driven gear.
  4.  
  5. Press behind second speed gear to remove 3rd/4th synchronizer assembly, 3rd speed gear and 2nd speed gear along with 3rd speed gear bushing and thrust washer.
  6.  
  7. Remove 2nd speed synchronizer ring and keys.
  8.  
  9. Using a press, remove 1st speed gear bushing and 2nd speed synchronizer hub.
  10.  
  11. Without damaging the mainshaft, chisel out the 2nd speed gear bushing.
  12.  

INSPECTION

Wash all parts in cleaning solvent and inspect them for excessive wear or scoring.

The third and fourth speed clutch sleeve should slide freely on the clutch hub, but the clutch hub should fit snugly on the shaft splines. Third speed gear must be running fit on mainshaft bushing and mainshaft bushing should be press fit on the shaft. First and reverse sliding gear must be sliding fit on the synchronizer hub and must not have excessive radial or circumferential play. If the sliding gear is not free on hub, inspect for burrs which may have rolled up on the front end of half tooth internal splines and remove by honing as necessary.

MAINSHAFT ASSEMBLY
  1. Lubricate with E.P. oil and press onto mainshaft. 1st, 2nd and 3rd speed gear bushings are sintered iron, exercise care when installing.
  2.  
  3. Press 1st and 2nd speed synchronizer hub onto mainshaft with annulus toward rear of shaft.
  4.  
  5. Install 1st and 2nd synchronizer keys and springs.
  6.  
  7. Press 1st speed gear bushing onto mainshaft until it bottoms against hub. Lubricate all bushings with E.P. oil before installation of gears.
  8.  
  9. Install synchronizer blocker ring and 2nd speed gear onto mainshaft and against synchronize hub. Align synchronizer key slots with keys in synchronizer hub.
  10.  
  11. Install 3rd speed gear thrust washer onto mainshaft inserting washer tang in slotted shaft. Then press 3rd speed gear bushing onto mainshaft against thrust washer.
  12.  
  13. Install 3rd speed gear and synchronizer blocker ring against 3rd speed gear thrust washer.
  14.  
  15. Align synchronizer key ring slots with synchronizer assembly keys and drive 3rd and 4th synchronizer assembly onto mainshaft. Secure assembly with snapring.
  16.  
  17. Install reverse driven gear with fork groove toward rear.
  18.  
  19. Install 1st speed gear against 1st and 2nd synchronizer hub. Install 1st speed gear thrust washer.
  20.  

COUNTERSHAFT DISASSEMBLY
  1. Remove front countergear retaining ring and thrust washer. Do not re-use this snapring or any others.
  2.  
  3. Press countershaft out of clutch countergear assembly.
  4.  
  5. Remove clutch countergear and 3rd speed countergear retaining rings.
  6.  
  7. Press shift from 3rd speed countergear.
  8.  

COUNTERSHAFT ASSEMBLY
  1. Press the 3rd speed countergear onto the shaft. Install gear with marked surface toward front of shaft.
  2.  
  3. Using snapring pliers, install new 3rd speed countergear retaining ring.
  4.  
  5. Install new clutch countergear rear retaining ring. Do not overstress snapring. Ring should fit tightly in groove with no side play.
  6.  
  7. Press countergear onto shaft against snapring.
  8.  
  9. Install clutch countergear thrust washer and front retaining ring.
  10.  

TRANSMISSION UNIT ASSEMBLY
  1. Lower the countergear into the case.
  2.  
  3. Place reverse idler gear in transmission case with gear teeth toward the front. Install idler gear shaft from rear to front, being careful to have slot in end of shaft facing down and flush with case.
  4.  
  5. Install mainshaft assembly into case with rear of shaft protruding out rear bearing hole in case. Rotate case onto front end. Install 1st speed gear thrust washer on shaft, if not previously installed.
  6.  
  7. Install snapring on bearing O.D. and place rear mainshaft bearing on shaft. Drive bearing onto shaft and into case.
  8.  
  9. Install synchronizer cone on mainshaft and slide rearward to clutch hub. Make sure three cut out sections of 4th speed synchronizer cone align with three clutch keys in clutch assembly.
  10.  
  11. Install snapring on clutch gear bearing O.D. Index cut out portion of clutch gear teeth to obtain clearance over countershaft drive gear teeth and install into case.
  12.  
  13. Install the clutch gear bearing retainer and gasket and tighten to 15-18 ft. lbs. (20-24 Nm).
  14.  
  15. Rotate the case onto the front end.
  16.  
  17. Install snapring on countergear rear bearing O.D. and drive bearing into place. Install snapring on countershaft at rear bearing.
  18.  
  19. Tap countergear front bearing assembly into case.
  20.  
  21. Install countergear front bearing cap and new gasket and tighten to 20-30 inch lbs. (2.2-3.4 Nm).
  22.  
  23. Slide speedometer drive gear over mainshaft to bearing.
  24.  
  25. Install rear bearing retainer with new gasket. Be sure snapring ends are in lube slot and cut out in bearing retainer. Install bolts and tighten to 15-18 ft. lbs. (20-24 Nm). Install the brake backing plate assembly on those models having driveshaft brake.
  26.  

On models equipped with 4-wheel drive, install rear locknut and washer and tighten it to 120 ft. lbs. (163 Nm). Bend washer tangs to fit slots in nut.

  1. Install parking brake drum and/or universal joint flange. Lightly oil seal surface.
  2.  
  3. Lock transmission in two gears at once. Install universal joint flange locknut and tighten to 90-120 ft. lbs. (122 Nm).
  4.  
  5. Move all transmission gears to neutral except the reverse idler gear which should be engaged approximately 3 / 8 in. (leading edge of reverse idler gear taper lines up with the front edge of the 1st speed gear). Install cover assembly and gasket. Shifting forks must slide into their proper positions on clutch sleeves and reverse idler gear. Forks must be positioned as in removal.
  6.  
  7. Install cover attaching bolts and gearshift lever and check operation of transmission.
  8.  

Muncie 4-Speed (Side Cover)

See Figure 7



Click image to see an enlarged view

Fig. Fig. 7: Exploded view of the Muncie 4-speed manual transmission with the side cover

TRANSMISSION CASE DISASSEMBLY
  1. Drain the lubricant. Remove the side cover and the shift forks.
  2.  
  3. Remove the clutch gear bearing retainer. Remove the bearing-to-gear stem snapring and pull out on the clutch gear until a small pry bar can be inserted between the bearing, the large snapring and case to pry the bearing off.
  4.  

The clutch gear bearing is a slip fit on the gear and in the case. Removal of the bearing will provide clearance for the clutch gear and the mainshaft removal.

  1. Remove the extension housing bolts, then remove the clutch gear, the mainshaft and the extension as an assembly.
  2.  
  3. Spread the snapring which holds the mainshaft rear bearing and remove the extension case.
  4.  
  5. Using a dummy shaft, drive the countershaft and its woodruff key out through the rear of the case. Remove the countergear assembly and the bearings.
  6.  
  7. Using a long drift, drive the Reverse idler shaft and the woodruff key through the rear of the case.
  8.  
  9. Expand and remove the 3rd/4th speed sliding clutch hub snapring from the mainshaft. Remove the clutch assembly, the 3rd gear blocking ring and the 3rd speed gear from the front of the mainshaft.
  10.  
  11. Press in the speedometer gear retaining clip and slide the gear off the mainshaft. Remove the rear bearing snapring from the mainshaft.
  12.  
  13. Using an arbor press, support the 1st gear on press plates, then press the 1st gear, the thrust washer, the spring washer, the rear bearing and snapring from the rear of the mainshaft.
  14.  

Be sure to center the gear, the washers, the bearings and the snapring when pressing the rear bearing.

  1. Expand and remove the 1st/2nd sliding clutch hub snapring from the mainshaft, then remove the clutch assembly, the 2nd speed blocking ring and the 2nd speed gear from the rear of the mainshaft.
  2.  

After thoroughly cleaning the parts and the transmission case, inspect and replace the damaged or worn parts. When checking the bearings, do not spin them at high speeds. Clean and rotate the bearings by hand to detect the roughness or unevenness. Spinning can damage the balls and the races.

TRANSMISSION CASE ASSEMBLY
  1. Grease both inside ends of the countergear. Install a dummy shaft into the countergear, then load a row of roller bearings (27) and thrust washers at each end of the countergear.
  2.  
  3. Position the countergear assembly into the case through the rear opening. Place a tanged thrust washer at each end of the countergear.
  4.  
  5. Install the countergear shaft and woodruff key from the rear of the case.
  6.  

Make sure that the shaft engages both thrust washers and that the tangs align with their notches in the case.

  1. Install the Reverse idler gear, the shaft and the woodruff key. Install the extension-to-rear bearing snapring. Assemble the extension housing over the rear of the mainshaft and onto the rear bearing.
  2.  
  3. Install the 14 mainshaft pilot bearings into the clutch opening and the 4th speed blocking ring onto the clutching surface of the clutch gear (with the clutching teeth facing the gear).
  4.  
  5. Assemble the clutch gear, the pilot bearings and the 4th speed blocking ring unit over the front of the mainshaft. Do not assemble the bearing to the gear at this point.
  6.  

Be sure that the blocking ring notches align with the 3rd/4th synchronizer assembly keys.

  1. Install the extension-to-case gasket and secure it with grease. Install the clutch gear, the mainshaft and the extension housing as an assembly. Install the extension-to-case bolts (apply sealer to the bottom bolt) and tighten to 45 ft. lbs. (61 Nm).
  2.  
  3. Install the outer snapring on the front bearing and place the bearing over the stem of the clutch gear and into the case bore.
  4.  
  5. Install the snapring to the clutch gear stem. Install the clutch gear bearing retainer and the gasket, with the retainer oil return hole at the bottom.
  6.  
  7. Place the synchronizer sleeves into the Neutral positions and install the cover, the gasket and the fork assemblies to the case; be sure the forks align with the synchronizer sleeve grooves. Tighten the cover bolts to 22 ft. lbs. (30 Nm).
  8.  

MAINSHAFT ASSEMBLY

Install the following parts with the front of the mainshaft facing up:

  1. Install the 3rd speed gear with the clutching teeth up; the rear face of the gear will abut with the mainshaft flange.
  2.  
  3. Install a blocking ring (with the clutching teeth down) over the 3rd speed gear synchronizing surface.
  4.  

The four blocking rings are the same.

  1. Press the 3rd/4th synchronizer assembly (with the fork slot down) onto the mainshaft splines until it bottoms.
  2.  

The blocking ring notches must align with the synchronizer assembly keys.

  1. Install the synchronizer hub-to-mainshaft snapring; both synchronizer snaprings are the same.
  2.  

Install the following parts with the rear of the mainshaft facing up:

  1. Install the 2nd speed gear with the clutching teeth up; the front face of the gear will abut with the flange on the mainshaft.
  2.  
  3. Install a blocking ring (with the clutching teeth down) over the 2nd speed gear synchronizing surface.
  4.  
  5. Press the 1st/2nd synchronizer assembly (with the fork slot down) onto the mainshaft.
  6.  

The blocking ring notches must align with the synchronizer assembly keys.

  1. Install the synchronizer hub-to-mainshaft snapring.
  2.  
  3. Install a blocking ring with the notches down so they align with the 1st/2nd synchronizer assembly keys.
  4.  
  5. Install the 1st gear with the clutching teeth down. Install the 1st gear thrust washer and the spring washer.
  6.  
  7. Press the rear ball bearing (with the slot down) onto the mainshaft. Install the snapring. Install the speedometer gear and clip.
  8.  

New Process (89mm)

See Figures 8 and 9



Click image to see an enlarged view

Fig. Fig. 8: Exploded view of the New Process (89mm) manual transmission



Click image to see an enlarged view

Fig. Fig. 9: New Process manual transmission key list

TRANSMISSION DISASSEMBLY
  1. Thoroughly clean the exterior of the transmission assembly.
  2.  
  3. Remove drain plug and drain lubricant from transmission.
  4.  
  5. Shift transmission into neutral position. Remove reverse shift lever, side cover bolts, side cover and shift forks. Remove reverse detent spring and ball from base in side of case.
  6.  
  7. Remove extension housing bolts and rotate the extension on the output shaft to expose the rear of the countershaft. Clearance has been provided on the extension in the inverted position to gain access for the countershaft removal.
  8.  
  9. With a centerpunch or drill, make a hole in the countershaft expansion plug at the front of the case.
  10.  
  11. Using this hole, push the countershaft rearward until the woodruff key is exposed. Remove key and push the countershaft forward against the expansion plug. Using a brass drift, tap the countershaft forward until the plug is driven out of the case.
  12.  
  13. Using tool J-29793 at the front of the countershaft, drive the shaft out of the rear of the case. Tool J-29793 will now hold the roller bearings in position within the gear bore. Lower countershaft gear to bottom of case.
  14.  
  15. Rotate the extension housing back to its normal position.
  16.  
  17. Remove the drive gear bearing retainer bolts and slide retainer and gasket off the gear assembly.
  18.  
  19. Using a brass drift, tap the gear and bearing assembly forward and remove through front of case. Replacement of the drive gear or bearing require no further disassembly of the transmission. Replace the failed part and reassemble the transmission.
  20.  
  21. Slide third and overdrive (O/D) synchronizer sleeve slightly forward, slide reverse idler gear to center of its shaft, then using a soft faced hammer, tap on extension housing in a rearward direction. Slide housing and mainshaft assembly out and away from case.
  22.  
  23. Remove countershaft gear from bottom of case.
  24.  
  25. Remove the reverse idler gear shaft from transmission case. To remove the shaft, use a 3 / 8 in. x 3 1 / 2 in. bolt with a free spinning nut and a -- deep socket 3 / 8 in. drive. Place the bolt and socket in the case with the socket against the shaft and the head of the bolt against the case. Holding the head of the bolt, turn nut against the socket pushing shaft through its bore. Remove gear from shaft and remove shaft with woodruff key from transmission case.
  26.  
  27. Remove reverse gear shift lever from case by pushing shaft inward and remove it from the case. Remove O-ring and retainer from case bolt.
  28.  
  29. Remove backup light switch from case.
  30.  

MAINSHAFT DISASSEMBLY
  1. Remove snapring that retains 3rd and O/D synchronizer clutch gear and sleeve assembly. Then slide 3rd and O/D synchronizer assembly off end of mainshaft.
  2.  
  3. Slide O/D gear and stop ring off mainshaft. Mark and separate synchronizer parts for cleaning and inspection.
  4.  
  5. Using long nose pliers, spread snapring that retains mainshaft ball bearing in extension housing, then pull mainshaft assembly out of the extension housing.
  6.  
  7. Remove speedometer drive gear from mainshaft.
  8.  
  9. Remove snapring that retains mainshaft bearing on the shaft. Remove bearing from mainshaft by inserting steel plate on the front side 1st gear, then press mainshaft through bearing. (Be careful not to damage gear teeth).
  10.  
  11. Remove bearing, bearing retainer ring, 1st gear, and 1st speed stop ring from the shaft.
  12.  
  13. Remove snapring that retains 1st and 2nd clutch gear and sleeve assembly. Then slide 1st and 2nd gear and sleeve assembly from the mainshaft. Remove 2nd gear. Before cleaning, mark all parts for reassembly.
  14.  
  15. Inspect mainshaft gear bearing surfaces for signs of wear, scoring or any condition that would not allow shaft to be used.
  16.  
  17. Remove tool J-29793 from the countershaft gear, 76 needle type bearings, thrust washers and spacers.
  18.  
  19. Remove outer snapring on the drive gear. Using an arbor press, remove bearing from drive gear, if bearing is to be replaced.
  20.  
  21. Remove inner snapring and 16 bearing rollers from cavity of drive gear.
  22.  

SYNCHRONIZER KEYS AND SPRINGS REPLACEMENT

The synchronizer hubs and sliding sleeves are a selected assembly and should be kept together as originally assembled, but the keys and springs may be replaced if worn or broken.

  1. If relation of hub an sleeve are not already marked, mark for assembly purposes.
  2.  
  3. Push the hub from the sliding sleeve, the keys will fall free and the spring may be easily removed.
  4.  
  5. Place the keys in position and while holding them in place, slide the sleeve onto the hub, aligning the marks made before disassembly.
  6.  
  7. Place the two springs in position (one on each side of hub), so all three keys are engaged by both springs.
  8.  

EXTENSION OIL SEAL AND/OR BUSHING REPLACEMENT
  1. Pry oil seal out of extension housing, using a screwdriver or small chisel.
  2.  
  3. Drive the brushing out of the housing, using tool J-8092 with J-21424-9.
  4.  
  5. Slide a new brushing tool J-23596 and drive bushing into place.
  6.  
  7. Position a new seal in opening of extension housing and drive it into the housing with tool J-21426.
  8.  

DRIVE GEAR BEARING RETAINER OIL SEAL REPLACEMENT
  1. Pry out old seal.
  2.  
  3. Using a new seal, install new seal into retainer using Tool J-23097 until it bottoms in bore. Lubricate I.D. of seal with transmission lubricant.
  4.  

TRANSMISSION SIDE COVER

The following three steps need only be done if oil leakage is visible around gearshift lever shifts, or the interlock levers are cracked.

  1. Remove the nuts that attach shift operating levers to the shafts. Disengage levers from flats on shafts and remove. Make sure shafts are free of burrs before removal, otherwise the bores may be scored resulting in leakage after assembly.
  2.  
  3. Pull gearshift lever shafts out of cover.
  4.  
  5. Remove O-ring retainers and O-rings from housing.
  6.  
  7. Remove E-ring from interlock lever pivot pin and remove interlock levers and spring from cover.
  8.  
  9. To assemble side cover, install interlock levers on pivot pin and fasten with E-ring. Use pliers to install spring on interlock lever hangers.
  10.  
  11. Grease housing bores and push each shaft into its proper bore followed by greased O-ring and retainer.
  12.  
  13. Install operating levers and tighten. Be sure 3rd-O/D operating levers point downward.
  14.  

COUNTERGEAR ASSEMBLY
  1. Coat inside bore of countergear at each end with a thin film of grease and install spacer with Tool J-29793 into gear. Center spacer and arbor.
  2.  
  3. Install 19 roller bearings, followed by a spacer ring and 19 more bearings and a spacer ring into each end of gear.
  4.  
  5. If countershaft thrush washers are worn or scored, install new thrust washers. Coat washers with grease and install one at the front of the countergear on the arbor with the tang side facing the case bore. Install the other washer after the countergear assemble is positioned in the bottom of the case.
  6.  

DRIVE GEAR ASSEMBLY
  1. Press drive gear bearing on drive gear seating bearing fully against shoulder on gear. Be sure outer snapring groove is toward the front.
  2.  
  3. Install a new snapring on shaft to retain bearing. Be sure snapring is seated. This snapring is a select fit for minimum end-play.
  4.  
  5. Place drive gear in a vise (with soft jaws), then install 16 bearing rollers in cavity of shaft. Coat bearing rollers with grease, then install retaining snapring in its groove.
  6.  

MAINSHAFT ASSEMBLY
  1. Slide second gear over mainshaft (synchronizer cone toward rear) and down against shoulder on shaft.
  2.  
  3. Slide 1st/2nd synchronizer assembly (including stop ring with lugs indexed in hub slots) over mainshaft, down against 2nd gear cone and secure with a new snapring. Slide next stop ring over shaft and index lugs into clutch hub slots.
  4.  
  5. Slide first gear (synchronizer cone toward clutch sleeve gear just installed) over mainshaft into position against clutch sleeve gear.
  6.  
  7. Install mainshaft bearing retainer ring, followed by mainshaft rear bearing.
  8.  

Using an arbor and a suitable tool, drive or press bearing down into position. Install a new snapring on shaft to secure bearing. This snapring is a select fit for minimum end-play.

  1. Install partially assembled mainshaft into extension housing far enough to engage bearing retaining ring in slot in extension housing. Expand snapring with pliers so that mainshaft ball bearing can move in and bottom against its thrust shoulder in extension housing. Release ring and seat it all around its groove in extension housing.
  2.  
  3. Slide overdrive gear over mainshaft (with synchronizer cone toward front) followed by O/D gear stop ring.
  4.  
  5. Install 3rd-O/D synchronizer clutch gear assembly on mainshaft (shift fork slot toward rear) against O/D gear. Be sure to index rear stop ring with clutch gear struts. Install retaining snapring.
  6.  
  7. Using grease, position front stop ring over clutch gear, again indexing ring lugs with struts.
  8.  

TRANSMISSION ASSEMBLY
  1. Place the transmission case on its side with the shift cover opening toward the assembler.
  2.  
  3. Install countergear assembly into the case aligning the tangs on the front washer with the slots in the case. Next install the rear washer aligning the tans with the slot at the rear of the case and then let the countergear rest in the bottom of the case. (Be sure thrust washers stay in position).
  4.  
  5. Coat a new extension gasket with grease then place it in position on the extension.
  6.  
  7. Insert mainshaft assembly into the case tilting it as required to clear the countershaft gear.
  8.  
  9. Rotate the extension housing to expose the rear of the countershaft bore. Install one bolt to hole the extension in inverted position and prevent it from moving rearward.
  10.  
  11. Install drive gear assembly through the front of the case and position it in the front bore. Install outer snapring in bearing groove. Tap lightly into place using a soft faced hammer. If everything is in proper position, the outer snapring will bottom onto the case face without excessive effort. If not, check to see if a strut, roller bearing or a stop ring is out of position.
  12.  
  13. Raise the countergear assembly into position with the teeth meshed with the drive gear. Make sure thrust washer remain in position on ends of the arbor and tangs are aligned with slots in case.
  14.  
  15. Start the countershaft into the rear bore of the case and push forward until the shaft is approximately half way through the gear. Install woodruff key and push the shaft forward until end is flush with case. Remove arbor Tool J-29793.
  16.  
  17. Install reverse shift lever shaft in case bore followed by greased O-ring and retainer.
  18.  
  19. Remove extension housing bolt and rotate extension to provide clearance for installation of the reverse idler gear in end of case.
  20.  
  21. Push the shaft in far enough to position reverse idler gear on protruding end of shaft with fork slot toward rear. At the same time, engage slot with reverse shift fork.
  22.  
  23. Install woodruff key on shaft and install bolts. Tighten the housing bolts to 75 ft. lbs. (102 Nm).
  24.  
  25. Align extension housing to case and install bolts. Tighten the housing bolts to 50 ft. lbs. (68 Nm).
  26.  
  27. Install the drive gear bearing retainer and gasket. Coat the threads with sealing compound, then install the bolts and tighten to 30 ft. lbs. (41 Nm).
  28.  
  29. Install new expansion plug coated with sealing compound in countershaft bore at front of case.
  30.  
  31. Position both synchronizer sleeves in neutral. Place the 1st/2nd shift fork into the groove of the 1st/2nd synchronizer sleeve. Slide reverse idler gear to neutral.
  32.  
  33. Rotate each shift lever to neutral position (straight up) and install 3rd/overdrive shift fork into its bore and under both interlock levers.
  34.  
  35. Position side cover gasket on case using grease to retain it. Install reverse detent ball followed by the spring into its bore in the case.
  36.  
  37. Lower the side cover onto the case guiding the 3rd/overdrive shift fork into the synchronizer groove, then lead the shaft of the 1st/2nd shift fork into its bore in the side cover. Hold the reverse interlock link against the 1st/2nd shift lever to provide clearance as the side cover is lowered into position. To finish the installation of the side cover, use a screwdriver and raise the interlock lever against its spring tension to allow the 1st/2nd shift fork to slip under the levers. Be sure the reverse detent spring is positioned in the cover bore.
  38.  
  39. Eight of the side cover bolts are shoulder bolts with one having a longer shoulder which acts as a dowel to accurately locate the side cover. The remaining two bolts are standard bolts. Install cover bolts finger tight and shift through all gears to insure proper operation.
  40.  
  41. Tighten the side cover bolts evenly to a torque of 15 ft. lbs. (20 Nm).
  42.  
  43. Install the reverse shift lever, retaining nut and tighten to 18 ft. lbs. (24 Nm).
  44.  
  45. Shift the transmission into each gear to insure correct shift travel and smooth operation. The reverse shift lever and 1st/2nd shift lever have cam surfaces which mate in reverse position to lock the 1st/2nd lever, fork and synchronizer in neutral position. Slight motion of the 1st/2nd shift lever toward low gear is normal during shifting into reverse gear.
  46.  
  47. Install the backup light switch and tighten to 15 ft. lbs. (20 Nm).
  48.  

 
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