Honda Civic/CRX/del Sol 1984-1995 Repair Guide

S20 Series Transaxle

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BEFORE DISASSEMBLY



See Figures 1 and 2

Cleanliness is an important factor in the overhaul of the manual transaxle. Before opening up the unit, the entire outside of the transaxle assembly should be cleaned, preferably with a high pressure washer such as a car wash spray unit. Dirt entering the transaxle internal parts will negate all the time and effort spent on the overhaul. During inspection and reassembly all parts should be thoroughly cleaned with solvent then dried with compressed air. Wiping cloths and rags should not be used to dry parts.

Wheel bearing grease, long used to hold thrust washers and lube parts, should not be used. Lube seals with clean transaxle oil and use ordinary unmedicated petroleum jelly to hold the thrust washers and to ease the assembly of seals, since it will not leave a harmful residue as grease often will. Do not use solvent on neoprene seals, if they are to be reused, or thrust washers.

Before installing bolts into aluminum parts, always dip the threads into clean transaxle oil. Antiseize compound can also be used to prevent bolts from galling the aluminum and seizing. Always use a torque wrench to keep from stripping the threads. The internal snaprings should be expanded and the external rings should be compressed, if they are to be reused. This will help ensure proper seating when installed.



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Fig. Fig. 1: Exploded view of the transaxle assembly-S20 series transaxle



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Fig. Fig. 2: Transaxle component key list

TRANSAXLE DISASSEMBLY



See Figures 3, 4, 5 and 6

  1. Remove the reverse light switch.
  2.  



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Fig. Fig. 3: Remove these components from the transaxle case-S20 series transaxle

  1. Remove the back-up light switch.
  2.  
  3. Remove the transaxle hanger B.
  4.  
  5. Remove the bolts attaching the transaxle housing to the clutch housing in a crisscross pattern in several steps.
  6.  
  7. Remove the 32mm sealing bolt.
  8.  
  9. Reach into the hole and expand the countershaft ball bearing snapring, removing it from the groove.
  10.  
  11. Separate the transaxle housing from the clutch housing and wipe it clean of sealant.
  12.  
  13. Remove the 10mm sealing bolt and oil gutter plate from the transaxle housing.
  14.  



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Fig. Fig. 4: Measure the shift fork clearance before removing the fork-S20 series transaxle

  1. Before removing the reverse shift fork, measure the clearance between the reverse shift fork and the shift piece pin. The specification is 0.002-0.02 in. (0.05-0.5mm). If not within specification, measure the width of the L-groove in the reverse shift fork. The maximum width is 0.285 in. (7.25mm). Replace the fork if the width exceeds the specification.
  2.  
  3. Measure the clearance between the reverse idler gear and the reverse shift fork. The specification is 0.020-0.07 in. (0.50-1.8mm). If not within specification, remove the fork and measure the distance between the shift fork pawls. The specification is 0.50-0.51 in. (12.7-13.0mm). Replace the shift fork if the pawl spread is too wide.
  4.  
  5. Remove the reverse shift fork if not already removed in the previous step. Remove the reverse idler shaft and reverse idler gear from the clutch housing.
  6.  
  7. Remove the interlock guide bolt from under the clutch housing.
  8.  



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Fig. Fig. 5: Removing the mainshaft and countershaft-S20 series transaxle

  1. Remove the shift arm B attaching bolt.
  2.  
  3. Remove the mainshaft and countershaft assemblies together with the shift forks and shafts.
  4.  

Before removing the mainshaft and countershaft assemblies, tape the mainshaft spline to protect it.

  1. Remove the differential assembly.
  2.  
  3. Remove the 28mm plug bolt and 1st/2nd select spring. Remove the shift arm C attaching bolt.
  4.  
  5. Remove the shift arm shaft, reverse selector spring, reverse return selector, shift arm C, interlock, shift arm B, steel ball, spring and spring collar. Inspect all parts for wear and damage, especially the shift rod detents.
  6.  
  7. Remove the shift arm A attaching bolt, spring bolt, spring and steel ball.
  8.  
  9. Remove the shift rod and boot from the clutch housing.
  10.  



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Fig. Fig. 6: Removing the shift rod assembly-S20 series transaxle

  1. Remove shift arm A, the reverse lock cam and the magnet.
  2.  
  3. If damaged, remove the countershaft needle bearing and oil guide plate from the clutch housing using the adjustable bearing remover 07736-A01000A and a slide hammer.
  4.  
  5. Remove the mainshaft bearing and oil seal from the clutch housing.
  6.  
  7. Remove the differential oil seals.
  8.  

COMPONENT DISASSEMBLY AND ASSEMBLY



Shift Fork Shafts

See Figure 7



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Fig. Fig. 7: Shift fork assembly-S20 series transaxle

DISASSEMBLY

Do not lose the spring loaded detent parts while disassembling the shift forks and shafts.

  1. Remove the roll pin from the shift piece.
  2.  
  3. Remove the 5th and 3rd/4th shift forks from the shaft.
  4.  
  5. Remove the shift piece from the shaft.
  6.  
  7. Remove the roll pin and remove the 1st/2nd shift fork from its shaft.
  8.  

INSPECTION
  1. Inspect the shift fork bores for scoring and excessive wear.
  2.  
  3. Inspect the shift fork pawls for cracks and wear.
  4.  
  5. Inspect the shafts for scoring, damage and excessive wear. Pay special attention to the detent groves.
  6.  
  7. Inspect the detent balls for wear and the springs for rust and deformation.
  8.  

ASSEMBLY

Before reassembling, use solvent to clean all the parts, dry them and lubricate any parts that contact in the assembly. Install the shift fork shaft with its detents facing the hole where the balls are inserted. The steel balls are all the same size (5/16 in.).

  1. Install the 1st/2nd shift fork on its shaft. Install the roll pin.
  2.  
  3. Install the shift piece on the shaft.
  4.  
  5. Install the 5th and 3rd/4th forks on the shaft.
  6.  
  7. Install the roll pin.
  8.  

Mainshaft Assembly
CHECKING CLEARANCES

See Figures 8, 9 and 10

Before disassembling the mainshaft assembly, perform the following measurements. If any measurement is not within specifications, disassemble the mainshaft assembly and replace parts as required.

If all measurements are within specifications, there is no reason to disassemble the mainshaft assembly, providing there is no damage to any of its components.



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Fig. Fig. 8: Mainshaft thrust shim selection chart-S20 series transaxle for D15B7, D15B8, D15Z1 engines



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Fig. Fig. 9: Mainshaft thrust shim selection chart-S20 series transaxle for D16Z6 engine



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Fig. Fig. 10: Measuring the mainshaft thrust-S20 series transaxle for D16Z6 engine

  1. Push down on the bearing race with a suitable socket and measure the clearance between 2nd and 3rd gears. The specification is 0.002-0.013 in. (0.06-0.33mm). If not within specifications, disassemble the mainshaft and check the thickness of 3rd gear. The specification is 1.187 in.-1.192 in. (30.15mm-30.27mm). If the thickness of 3rd gear is les than specification replace it with a new one. If the thickness of 3rd gear is within specification, replace the 3rd/4th gear synchro hub with a new one.
  2.  

The 3rd/4th and 5th synchro hubs are installed with a machine press. You will need access to a press, or a competent machine shop that will assist you with various operations of the overhaul. Or, you may opt to completely turn the job over to a qualified shop.

  1. Measure the clearance between 4th gear and the spacer collar. The specification is 0.002-0.012 in. (0.06-0.31mm). If the clearance exceeds the service limit, measure the distance on the spacer collar. The specification is 0.898-0.900 in. (22.81-22.86mm). If the distance is less than the service limit, replace the spacer collar with a new one.
  2.  
  3. If the distance is within specification, measure the thickness of 4th gear. The specification is 1.183-1.188 in. (30.05-30.17mm). If the thickness of 4th gear is less than specification, replace 4th gear with a new one. If the thickness of 4th gear is within the service limit, replace the 3rd/4th synchro hub with a new one.
  4.  
  5. If the vehicle is a five-speed, measure the clearance between 5th gear and the spacer collar. The specification is 0.002-0.012 in. (0.06-0.30mm). If the clearance exceeds the specification, measure the distance on the spacer collar. The specification is 0.925-0.928 in. (23.51-23.56mm).
  6.  
  7. If the distance is not within specification, replace the spacer collar with a new one. If the distance is within the specification, measure the thickness of 5th gear. The specification is 1.116-1.121 in. (28.35-28.47mm). If the thickness of 5th gear is less than the specification, replace the 5th gear with a new one. If the thickness of 5th gear is within specification, replace the 4th gear synchro hub with a new one.
  8.  

DISASSEMBLY

See Figures 11 and 12

  1. Remove the ball bearing using a bearing puller (as shown) from the end of the mainshaft.
  2.  



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Fig. Fig. 11: Bearing puller being used to remove the ball bearing from the mainshaft end-S20 series transaxle

  1. Using a machine press, support the 4th gear on steel blocks and press the mainshaft out of the 5th gear synchro hub if equipped.
  2.  


WARNING
Do not use a jaw type puller as it may damage the gear teeth.



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Fig. Fig. 12: Align the attachment and support the gear for removal on the press as shown-S20 series transaxle

  1. Support the 3rd gear on steel blocks and press the mainshaft from the 3rd/4th synchro hub.
  2.  
  3. Remove 3rd gear and the needle bearing.
  4.  

INSPECTION

See Figures 13 and 14

  1. Inspect the needle bearings for wear or damage.
  2.  
  3. Inspect the inside of the synchro rings for wear.
  4.  
  5. Install each hub in its mating sleeve and check for freedom of movement. If replacement is required, replace them as an assembly.
  6.  
  7. Inspect the synchro ring teeth and matching teeth on the gears for wear in the form of rounding.
  8.  
  9. Inspect the gear hub thrust and cone surfaces for wear.
  10.  
  11. Inspect the teeth on all gears for uneven wear, scoring, galling or cracks.
  12.  
  13. Measure the mainshaft at points A,B,C and D as shown in the accompanying drawing. Use the service limits listed to determine the servicability of the mainshaft.
  14.  



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Fig. Fig. 13: Measurement specifications for mainshaft-S20 series transaxle

  1. Place the mainshaft in V-blocks at both ends and use a dial indicator as shown to measure runout.
  2.  
  3. The maximum allowable runout is 0.0020 in. (0.05mm). Replace the mainshaft if any measurement is not within specifications.
  4.  



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Fig. Fig. 14: Measuring the runout of the mainshaft using a precision dial indicator-S20 series transaxle

ASSEMBLY

See Figures 15 and 16

When installing the 3rd/4th and 5th synchro hubs, support the shaft on the steel blocks and install the synchro hubs using a press.

  1. Support 2nd gear on steel blocks and install the 3rd/4th synchro hub using a press and a 35mm I.D. attachment (special tool No. 07746-0030400 or equivalent,) and a 40mm I.D. driver (part No. 07746-030100 or equivalent.)
  2.  



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Fig. Fig. 15: Assembly of the mainshaft should look like this-S20 series transaxle

  1. Install the 3rd/4th synchro sleeve by aligning the stoppers of the 3rd/4th synchro sleeve and hub. The stoppers are mating gears that prevent the gears from aligning in any other way than as specified.
  2.  



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Fig. Fig. 16: The stoppers on the 3rd/4th synchro sleeve enable the correct engagement

  1. Install the 5th gear synchro hub using the 30mm I.D. attachment, (part No. 07746-0030300 or equivalent,) and the 40mm I.D. driver (part No. 07746-030100 or equivalent.)
  2.  
  3. Press on the ball bearing using the 30mm I.D. attachment and 40mm I.D. driver.
  4.  

MAINSHAFT SHIM SELECTION
  1. If they have not already been removed, remove the thrust shim(s), and oil guide plate from the transaxle housing.
  2.  
  3. Install the 3rd/4th synchro hub, spacer collar, 5th synchro hub (five-speed) or collar (four-speed) and ball bearing on the mainshaft. Make sure the clutch side ball bearing is not installed on the mainshaft. Install the assembly in the transaxle case.
  4.  
  5. Using a straight edge and feeler gauge, measure the distance between the end of the transaxle case and the thrust washer. Make the measurement at three places, average the results and record the final answer.
  6.  
  7. Install the clutch housing side bearing (without the spring washer) into the mainshaft and install the clutch housing on the transaxle housing temporarily. Measure the distance between the end of the clutch housing and the bearing inner race. Make the measurement at three places, average the results and record the final answer.
  8.  
  9. To select the proper shim(s), use the following formula: Step 3 + Step 4-0.95 = shim thickness. Select a shim or combination of shims that is equal to or close to the answer to the formula.
  10.  

Do not use more than two thrust shims.

CHECKING THRUST CLEARANCE

See Figure 17

  1. Install the selected shim(s) in the transaxle case.
  2.  
  3. Install the spring washer on the mainshaft, concave side facing mainshaft 1st gear.
  4.  
  5. Install the mainshaft in the clutch housing.
  6.  
  7. Clean all dirt from the mating surfaces of the transaxle and clutch housings and install the transaxle housing to the clutch housing with several bolts spaced evenly around the housing.
  8.  
  9. Tap the mainshaft with a plastic hammer.
  10.  
  11. Install the collar and shaft holder of the mainshaft thrust clearance inspection tool 07GAJ-PG20101 to the mainshaft and tighten the three Allen bolts into the groove below the splines. Make sure they are positioned correctly and not digging into the splines. First, turn the bolt on the thinnest side of the tool just enough to keep the tool away from the splines. Then turn the remaining bolts equally to secure the tool off center.
  12.  
  13. Position a dial indicator so the pin rests on the outer circumference of the tip of the mainshaft.
  14.  
  15. Turn the bolt clockwise and read the clearance.
  16.  

Do not turn the bolt more than 60° after the needle of the dial indicator has stopped increasing.

  1. The clearance specification is 0.004-0.007 in. (0.11-0.18mm). If the clearance is not within specifications, repeat the entire procedure. Do not continue until the correct clearance has been obtained.
  2.  
  3. When the correct clearance has been obtained, disassemble the transaxle and assemble the mainshaft completely.
  4.  



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Fig. Fig. 17: Special tools used to check mainshaft thrust clearance-S20 series transaxles

Countershaft Assembly

See Figure 18



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Fig. Fig. 18: Exploded view of the countershaft assembly-S20 series transaxle

CLEARANCE INSPECTION
  1. Measure the clearance between the countershaft and 1st gear. The specification is 0.001-0.009 in. (0.33-0.22mm).
  2.  
  3. If the clearance is greater than the specification, measure the thickness of 1st gear. The specification is 1.195-1.198 in. (30.36-30.44mm). If the thickness is less than the specification, replace 1st gear with a new one. If 1st gear is within the specification, replace the 1st/2nd geaer synchro hub with a new one.
  4.  
  5. Measure the clearance between 2nd and 3rd gears. The specification is 0.001-0.009 in. (0.03-0.23mm).
  6.  
  7. If the clearance is greater than the specification, measure the thickness of the spacer collar. The specification is 1.260-1.262 in. (32.01-32.06mm).
  8.  
  9. If the thickness is less than the specification, replace the spacer collar with a new one. If the thickness is within the specification, measure the thickness of 2nd gear. If the thickness of 2nd gear is less than the specification, replace 2nd gear with a new one. If the thickness of 2nd gear is within the service limit, replace the spacer collar with a new one.
  10.  

DISASSEMBLY

A press and steel blocks should be used to remove the gears. A jaw-type puller can damage the gear teeth.

  1. Clamp the countershaft assembly securely in a vise with soft jaws (wood or hard plastic blocks contacting the countershaft)
  2.  
  3. Remove the locknut and lockwasher.
  4.  
  5. Remove the ball bearing using a bearing puller.
  6.  
  7. Using the steel blocks, support 4th gear and press the countershaft out of 5th and 4th gears.
  8.  
  9. Support 1st gear on steel blocks and press the countershaft out of 3rd gear.
  10.  

INSPECTION

See Figure 19

  1. Inspect the gear surfaces and bearing surfaces for wear and damage, then measure the countershaft at points A,B and C (as shown in the accompanying drawing). If any part of the countershaft is less than the limit, replace it with a new one.
  2.  



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Fig. Fig. 19: Measurement points and specifications to determine serviceability of the countershaft-S20 series transaxle

  1. Mount the countershaft in a pair of V-cut blocks and, using a dial indicator, rotate and inspect the runout. The specification is 0.001-0.002 in. (0.05-0.05mm). If the runout is greater than the service limit, replace the countershaft with a new one.
  2.  
  3. Install the hub in its mating sleeve and check for freedom of movement. If replacement is required, replace them as an assembly.
  4.  
  5. Inspect the synchro ring teeth and matching teeth on the gears for wear in the form of rounding.
  6.  
  7. Inspect the gear hub thrust and cone surfaces for wear.
  8.  
  9. Inspect the teeth on all gears for uneven wear, scoring, galling or cracks.
  10.  

ASSEMBLY

See Figure 20


WARNING
Press 3rd, 4th, 5th gears onto the shaft without lubrication. To avoid damage, use the steel blocks and a proper machine press.

It will be necessary to use special tools to press the gears in place. A 40mm I.D. driver, (part No. 07746-0030100 or equivalent); a 35mm I.D. attachment, (part No. 07746-0030400 or equivalent); a 30mm I.D. attachment, (part No. 07746-0030300 or equivalent.)

  1. Install the needle bearing, friction damper and 1st gear.
  2.  
  3. Install the synchro ring, spring, hub, reverse gear, spring and ring.
  4.  
  5. Install the spacer collar.
  6.  
  7. Install the needle bearing, the friction damper, 2nd, 3rd, 4th gear and 5th gear (five-speed) or collar (four-speed) and the other needle bearing.
  8.  
  9. Install the ball bearing.
  10.  
  11. Securely clamp the assembly in a soft-jaw bench vise and install the lockwasher and a new locknut. Tighten the locknut to 80 ft. lbs. (110 Nm), loosen it, then retorque it to the 80 ft. lbs. (110 Nm).
  12.  



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Fig. Fig. 20: Exploded view of countershaft gears and related components-S20 series transaxle

TRANSAXLE ASSEMBLY



See Figures 21 and 22



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Fig. Fig. 21: Exploded view of transaxle components-S20 series transaxle

  1. Install the new differential seals.
  2.  
  3. Install a new mainshaft bearing oil seal and install the bearing if it was removed.
  4.  
  5. Install the oil guide plate and countershaft needle bearing, if they were removed.
  6.  
  7. Install the shift rod with new boot. Place shift arm A in the clutch housing, then push the shift rod through the shift arm.
  8.  
  9. Install the steel ball, spring, bolt and new shift arm A attaching bolts. Tighten the attaching bolts to 21 ft. lbs. (29 Nm).
  10.  
  11. Install the spring collar, spring and steel ball.
  12.  
  13. Install shift arm B into the interlock.
  14.  
  15. Install the interlock assembly and shift arm C into the clutch housing. Install the shift arm shaft into the clutch housing, aligning the shift arm shaft holes with the holes in the shift arms B and C.
  16.  
  17. Install the reverse lock cam and magnet.
  18.  
  19. Install the differential assembly.
  20.  
  21. Install the spring washer to the bottom of the mainshaft with the concave side facing up and install the mainshaft, countershaft and shift forks together as assembly. Install the tab of the interlock assembly into the notches of the shift fork as the mainshaft and countershaft assemblies are lowered into the clutch housing.
  22.  
  23. Install a new shift arm B attaching bolt and tighten to 23 ft. lbs. (32 Nm).
  24.  
  25. Install the 1st/2nd selector spring and plug bolt and tighten to 40 ft. lbs. (55 Nm).
  26.  
  27. Apply a light coating of sealant (part number 08718-550000 or equivalent) to the interlock guide bolt and install in the proper hole under the clutch housing. Tighten the guide bolt to 29 ft. lbs. (41 Nm).
  28.  



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Fig. Fig. 22: Installing the mainshaft and countershaft-S20 series transaxle

  1. Install the reverse idler gear and idler gear shaft in the clutch housing.
  2.  
  3. Install the reverse shift holder.
  4.  
  5. Install the oil guide plate and selected shim(s) into the transaxle housing.
  6.  
  7. Thoroughly clean and dry the mating surfaces of the transaxle and clutch housings. Apply sealant (part number 08718-550000 or equivalent) to the mating surface of the clutch housing.
  8.  
  9. Install the transaxle housing to the clutch housing, being careful to line up the shafts.
  10.  
  11. Install the snapring to the countershaft ball bearing through the hole at the top of the transxle housing.
  12.  
  13. Tighten the bolts in the proper sequence to 21 ft. lbs. (29 Nm).
  14.  
  15. Apply a light coating of sealant (part number 08718-550000 or equivalent) to the 32mm sealing bolt and install.
  16.  
  17. Connect the breather tube. Install the cable bracket.
  18.  
  19. Install the reverse light switch.
  20.  

 
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