See Figure 1
- Drain the transmission lubricant.
- Use a pin punch and hammer to remove the offset lever-to-shift rail roll pin.
- Remove the extension housing adapter. Remove the housing and the offset lever as an assembly.
- Remove the detent ball and spring from the offset lever. Remove the roll pin from the extension housing or adapter.
- Remove the countershaft rear thrust bearing and race.
- Remove the transmission cover and shift fork assembly. Two of the transmission cover bolts are alignment type dowel pins. Mark their location so that they may be reinstalled in their original locations.
- Remove the reverse lever to reverse lever pivot bolt C-clip.
- Remove the reverse lever pivot bolt. Remove the reverse lever and fork as an assembly.
- Mark the position of the front bearing cap to case, then remove the bearing cap bolts and cap.
- Remove the front bearing race and the shims from the bearing cap. Use a small pry bar and remove the front seal from the bearing cap.
- Rotate the main drive gear shaft until the flat portion of the gear faces the countershaft, then remove the main drive gear shaft assembly.
- Remove the thrust bearing and 15 roller bearings from the clutch shaft. Remove the output shaft bearing race. Tap the output shaft with a plastic hammer to loosen it if necessary.
- Tilt the output shaft assembly upward and remove the assembly from the case.
- Carefully pull off the countershaft rear bearing with the proper puller after marking the position for reinstallation.
- Move the countershaft rearward and tilt it upward to remove it from the transmission case. Remove the countershaft bearing spacer.
- Remove the reverse idler shaft roll pin, then remove the reverse idler shaft and gear.
- Press off the countershaft front bearing. Use the appropriate pullers and remove the bearing from the main drive gear shaft.
- Remove the extension housing or adapter oil seal and remove the back-up light switch from the case.
OUTPUT SHAFT DISASSEMBLY
- Remove the thrust bearing washer from the front of the output shaft.
- Scribe matchmarks on the hub and sleeve of the 3rd-4th synchronizer so that these parts may be reassembled properly.
- Remove the 3rd-4th synchronizer blocking ring, sleeve and hub as an assembly.
- Remove the insert springs and the inserts from the 3rd-4th synchronizer and separate the sleeve from the hub.
- Remove the 3rd speed gear from the shaft.
- Remove the 2nd speed gear to output shaft snapring, the tabbed thrust washer and the 2nd speed gear from the shaft.
- Use an appropriate puller and remove the the output shaft bearing.
- Remove the 1st gear thrust washer, the roll pin, the 1st speed gear and the blocking ring.
- Scribe matchmarks on the 1st-2nd synchronizer sleeve and the output shaft.
- Remove the insert spring and the inserts from the 1st-reverse sliding gear, then remove the gear from the output hub.
OUTPUT SHAFT ASSEMBLY
- Coat the output shaft and the gear bores with transmission lubricant.
- Align the matchmarks and install the 1st-2nd synchronizer sleeve on the output shaft hub.
- Install the three inserts and two springs into the 1st-reverse synchronizer sleeve.
The tanged end of each spring should be positioned on the same insert but the open face of each spring should be opposite each other.
- Install the blocking ring and the 2nd speed gear onto the output shaft.
- Install the tabbed thrust washer and 2nd gear snapring in the output shaft; be sure that the washer is properly seated in the notch.
- Install the blocking ring and the 1st speed gear onto the output shaft, then install the 1st gear roll pin.
- Press the rear bearing onto the shaft.
- Install the remaining components onto the output shaft: The 1st gear thrust washer. The 3rd speed gear. The 3rd-4th synchronizer hub inserts and the sleeve (the hub offset must face forward). The thrust bearing washer on the rear of the countershaft.
COVER & FORKS DISASSEMBLY
- Place the selector arm plates and the shift rail centered in the Neutral position.
- Rotate the shift rail counterclockwise until the selector arm disengages from the selector arm plates; the selector arm roll pin should now be accessible.
- Pull the shift rail rearward until the selector contacts the 1st-2nd shift fork.
- 3 / 16 in. pin punch and remove the selector arm roll pin and the shift rail.
- Remove the shift forks, the selector arm, the roll pin and the interlock plate.
- Remove the shift rail oil seal and O-ring.
- Remove the nylon inserts and the selector arm plates from the shift forks.
Mark the position of the parts so that they may be properly installed.
COVER & FORK ASSEMBLY
- Attach the nylon inserts to the selector arm plates and through the shift forks.
- If removed, coat the edges of the shift rail plug with sealer and install the plug.
- Coat the shift rail and the rail bores with petroleum jelly, then slide the shift rail into the cover until the end of the rail is flush with the inside edge of the cover.
- Position the 1st-2nd shift fork into the cover; with the offset of the shift fork facing the rear of the cover. Push the shift rail through the fork. The 1st-2nd fork is the larger of the two forks.
- Position the selector arm and the C-shaped interlock plate into the cover, then push the shift rail through the arm. The widest part of the interlock plate must face away from the cover and the selector arm roll pin must face downward, toward the rear of the cover.
- Position the 3rd-4th shift fork into the cover with the fork offset facing the rear of the cover. The 3rd-4th shift selector arm plate must be positioned under the 1st-2nd shift fork selector arm plate.
- Push the shift rail through the 3rd-4th shift fork and into the front cover rail bore.
- Rotate the shift rail until the forward selector arm plate faces away from parallel to the cover.
- Align the roll pin holes of the selector arm and the shift rail and install the roll pin. The roll pin must be installed flush with the surface of the selector arm to prevent selector arm plate to pin interference.
- Install the O-ring into the groove of the shift rail oil seal, then install the oil seal carefully after lubricating it.
- Apply a coat of Loctite® 601, or equivalent, to the outer cage of the front countershaft bearing, then press the bearing into the bore until it is flush with the case.
- Apply petroleum jelly to the tabbed countershaft thrust washer and install the washer with the tab engaged in the corresponding case depression.
- Tip the transmission case on end and install the countershaft into the front bearing bore.
- Install the rear countershaft bearing spacer and coat the rear bearing with petroleum jelly. Install the rear countershaft bearing using the appropriate tools. The rear bearing is properly installed when 3mm is extended beyond the case surface.
- Position the reverse idler into the case (the shift lever groove must face rearward) and install the reverse idler shaft into the case. Install the shaft retaining pin.
- Install the output shaft assembly into the transmission case.
- Install the main drive gear bearing onto the main drive shaft using the appropriate tools. Coat the roller bearings with petroleum jelly and install them in the main drive gear recess. Install the thrust bearing and race.
- Install the 4th gear blocking ring onto the output shaft. Install the rear output shaft bearing race.
- Install the main drive gear assembly into the case, engaging the 3rd-4th synchronizer blocking ring.
- Install a new seal in the front bearing cap and in the rear extension or adapter.
- Install the front bearing into the front bearing cap but do not (at this time) install the shims. Temporarily install the cap to the transmission without applying sealer.
- Install the reverse lever, the pivot pin (coat the threads with non-hardening sealer) and the retaining C-clip. Be sure the reverse lever fork is engaged with the reverse idler gear.
- Coat the countershaft rear bearing race and the thrust bearing with petroleum jelly, then install the parts into the extension housing or adapter.
- Temporarily install the extension housing or adapter without sealer, tighten the retaining bolts slightly, but do not final torque them.
- Turn the transmission case on end and mount a dial indicator in position to measure output shaft end play. To eliminate end play the bearings must be preloaded from 0.025-0.130mm. Check the endplay. Select a shim pack that measures 0.025-0.130mm thicker than the measured endplay.
- Install the shims under the front bearing cap. Apply a 1 / 8 in. bead of RTV sealer to the cap. Align the reference marks and install the cap on the front of the transmission. Torque the mounting bolts to 15 ft. lbs. Recheck the output shaft end play, none should exist. Adjust if necessary.
- Remove the extension housing or adapter. Move the shift forks and synchronizer sleeves to their neutral position. Apply a Apply a 1 / 8 in. bead of RTV sealer to the cover to case mounting surface. Align the forks with their sleeves and carefully lower the cover into position. Center the cover and install the alignment dowels. Install the mounting bolts and tighten to 9 ft. lbs.
The offset lever to shift rail roll pin must be position vertically; if not, repeat Step 17.
- Apply a 1 / 8 in. bead of RTV sealer to the extension housing or adapter and install over the output shaft.
The shift rail must be positioned so that it just enters the shift cover opening.
- Install the detent spring into the offset lever and place the steel ball into the Neutral guide plate detent. Apply pressure to the detent spring and offset lever, then slide the offset lever on the shift rail and seat the extension housing or adapter plate against the transmission case. Install and tighten the mounting bolts to 25 ft. lbs.
- Install the roll pin into the offset lever and shift rail. Install the damper sleeve in the offset lever. Coat the back up lamp switch threads with sealer and install the switch, tighten to 15 ft. lbs.