Part 2
SYNCHRO SLEEVE, SYNCHRO HUBInspection
1. Inspect gear teeth on all synchro hubs and synchro sleeves for rounded off corners, which indicate wear.
2. Install each synchro hub in its mating synchro sleeve, and check for freedom of movement.
NOTE: If replacement is required, always replace the synchro sleeve and synchro hub as a set.
Installation
When assembling the synchro sleeve and synchro hub, be sure to match the three sets of longer teeth (120° apart) on the synchro sleeve with the three sets of deeper grooves in the synchro hub. Do not install the synchro sleeve with its longer teeth in the synchro hub slots because it will damage the spring ring.
SYNCHRO RING, GEAR
Inspection
1. Inspect the synchro ring and gear.
A: Inspect the inside of the synchro ring for wear.
B: Inspect the synchro sleeve teeth and matching teeth on the synchro ring for wear (rounded off).
C: Inspect the synchro sleeve teeth and matching teeth on the gear for wear (rounded off).
D: Inspect the gear hub thrust surface for wear.
E: Inspect the cone surface for wear and roughness.
F: Inspect the teeth on all gears for uneven wear, scoring, galling, and cracks.
2. Coat the cone surface of the gear with oil, and place the synchro ring on the matching gear. Rotate the ring, making sure that it does not slip.
Measure the clearance between the synchro ring and gear all the way around. Be sure to hold the synchro ring against the gear evenly while measuring the clearance.
If the clearance is less than the service limit, replace the synchro ring and synchro cone.
MAINSHAFT BEARING/OIL SEAL
Replacement
1. Remove the differential assembly.
2. Remove the ball bearing using the special tool as shown.
3. Remove the oil seal from the clutch side.
4. Drive the new oil seal in from the transmission side using the special tools as shown.
5. Drive the new ball bearing in from the transmission side using the special tools as shown.
COUNTERSHAFT BEARING
Replacement
1. Remove the retaining plate from the clutch housing.
2. Remove the needle bearing using the special tool, then remove the oil guide plate.
3. Position the oil guide plate and new needle bearing in the bore of the clutch housing.
NOTE: Position the needle bearing with the oil hole facing up.
4. Drive the needle bearing in using the special tools as shown.
5. Install the retaining plate, and stake the bolt heads into the groove in the retaining plate.
DIFFERENTIAL
Index
NOTE: If parts marked with an asterisk (*) were replaced, the tapered roller bearing preload must be adjusted.
Backlash Inspection
1. Place the differential assembly on V-blocks and install both axles.
2. Measure the backlash of both pinion gears.
If the backlash is not within the standard, replace the differential carrier.
Final Driven Gear Replacement
1. Remove the bolts in a crisscross pattern in several steps, then remove the final driven gear from the differential carrier.
NOTE: The final driven gear bolts have left-hand threads.
2. Install the final driven gear by tightening the bolts in a crisscross pattern in several steps.
Tapered Roller Bearing Replacement
NOTE:
- The tapered roller bearing and bearing outer race should be replaced as a set.
- Inspect and adjust the tapered roller bearing preload whenever the tapered roller bearing is replaced.
- Check the tapered roller bearings for wear and rough rotation. If the tapered roller bearings are OK, removal is not necessary.
1. Remove the tapered roller bearings using a bearing puller and a bearing separator as shown.
2. Install new tapered roller bearings using the special tool as shown.
NOTE: Drive the tapered roller bearings on until they bottom against the differential carrier.
Oil Seal Removal
1. Remove the differential assembly.
2. Remove the oil seal from the transmission housing.
3. Remove the oil seal from the clutch housing.
Bearing Outer Race Replacement
NOTE:
- The bearing outer race and tapered roller bearing should be replaced as a set.
- Inspect and adjust the tapered roller bearing preload whenever the tapered roller bearing is replaced.
1. Remove the oil seals from the transmission housing and clutch housing.
2. Drive the bearing outer race and thrust shim out of the transmission housing, or remove the bearing outer race and 75 mm shim from the clutch housing by heating the clutch housing to about 212°F (100°C) with a heat gun. Do not heat the clutch housing in excess of 212°F (100°C).
If the outer race was driven out, replace the thrust shim with a new one.
3. Install the thrust shim or 75 mm shim and the bearing outer race in the transmission housing and the clutch housing using the special tools as shown.
NOTE:
- Install the bearing outer race squarely.
- Check that there is no clearance between the bearing outer race, thrust shim or 75 mm shim, and housing.
4. Install the oil seal.
Tapered Roller Bearing Preload Adjustment
NOTE: If any of the items listed below were replaced, the tapered roller bearing preload must be adjusted.
- Transmission housing
- Clutch housing
- Differential carrier
- Tapered roller bearing and bearing outer race
- Thrust shim
- 75 mm shim
1. Remove the bearing outer race and thrust shim from the transmission housing.
Note these items before adjusting bearing preload:
- Install the thrust shim only on the transmission housing side.
- If the outer race was driven out, replace the thrust shim with a new one.
- Before adjusting the tapered roller bearing preload, let the transmission cool to room temperature if the bearing outer race was removed by heating the clutch housing.
2. First try the same size thrust shim that was removed.
CAUTION: Use only one thrust shim.
3. After installing the thrust shim, install -the bearing outer race in the transmission housing.
NOTE:
- Install the bearing outer race squarely.
- Check that there is no clearance between the bearing outer race, thrust shim and transmission housing.
4. With the mainshaft and countershaft removed, install the differential assembly, and torque the clutch housing and transmission housing.
NOTE: It is not necessary to use sealing agent between the housings.
TORQUE:
10 x 1.25 mm: 47 Nm (4.8 kgf.m, 35 ft. lbs.)
8 x 1.25 mm: 27 Nm (2.8 kgf-m, 20 ft. lbs.)
5. Rotate the differential assembly in both directions to seat the tapered roller bearings.
6. Measure the starting torque of the differential assembly at room temperature with the special tool and a torque wrench. Measure the tapered roller bearing preload in both directions.
7. If the tapered roller bearing preload is not within the standard, select the thrust shim which will give the correct tapered roller bearing preload from the following table.
NOTE: Changing the thrust shim to the next size will increase or decrease tapered roller bearing preload about 0.3 - 0.4 Nm (3 - 4 kgf-cm, 2.6 - 3.5 inch lbs.).
8. Recheck the tapered roller bearing preload.
9. How to select the correct thrust shim:
a. Compare the tapered roller bearing preload you get with the thrust shim that was removed, with the specified preload of 1.4 - 2.5 Nm (14 - 26 kgf-cm, 12 - 23 inch lbs.).
b. If your measured tapered roller bearing preload is less than specified, subtract yours from the specified.
If yours is more than specified, subtract the specified from your measurement.
For example with a 2.17 mm (0.0854 inch) thrust shim:
c. Each shim size up or down from standard makes about 0.3 - 0.4 Nm (3 - 4 kgf-cm, 2.6 - 3.5 inch lbs.) difference in tapered roller bearing preload.
In example (A), your measured tapered roller bearing preload was 1.9 Nm (20 kgf-cm, 18 inch lbs.) less than standard so you need a thrust shim five sizes thicker than standard (try the 2.32 mm (0.0913 inch) thrust shim, and recheck).
In example (B), your measurement was 0.8 Nm (8 kgf-cm, 7 inch lbs.) more than standard, so you need a thrust shim two sizes thinner (try the 2.11 mm (0-0831 inch) thrust shim, and recheck).
10. After adjusting the tapered roller bearing preload, assemble the transmission and install the transmission housing.
TORQUE:
10 x 1.25 mm: 47 Nm (4.8 kgf-m, 35 ft. lbs.)
8 x 1.25 mm: 27 Nm (2.8 kgf-m, 20 ft. lbs.)
11. Rotate the differential assembly in both directions to seat the tapered roller bearings.
MAINSHAFT THRUST CLEARANCE
Adjustment
1. Remove the 78 mm shim and oil guide plate from the transmission housing.
2. Install the 3rd/4th synchro hub, spacer collar, 5th synchro hub, spacer, and ball bearing on the mainshaft, then install the above assembly in the transmission housing.
3. Install the washer on the mainshaft.
4. Measure distance (j) between the end of the transmission housing and washer, using straight edge and vernier caliper. Measure at three locations and average the reading.
5. Measure distance & between the end of the clutch housing and bearing inner race, using a straight edge and depth gauge. Measure at three locations and average the readings.
6. Select the proper 78 mm shim from the chart by using the formula below.
Shim Selection Formula:
From the measurements you made in steps 4 and 5:
a. Add distance (C) (step 5) to distance (B) (step 4).
b. From this number, subtract 0.93 (which is the midpoint of the flex range of the clutch housing bearing spring washer).
c. Take this number and compare it to the available shim sizes in the chart.
- Try the 1.68 mm (0.0661 inch) shim.
78 mm SHIM
7. Check the thrust clearance in the manner described below.
NOTE: Measurement should be made at normal room temperature.
a. Install the 78 mm shim selected and oil guide plate in the transmission housing.
b. Install the spring washer and washer on the ball bearing.
NOTE:
- Clean the spring washer, washer and thrust shim thoroughly before installation.
- Install the spring washer, washer and thrust shim properly.
c. Install the mainshaft in the clutch housing.
d. Place the transmission housing over the mainshaft and onto the clutch housing.
e. Tighten the clutch and transmission housings with several 8 mm and 10 mm bolts.
NOTE: It is not necessary to use sealing agent between the housings.
f. Tap the mainshaft with a plastic hammer.
g. Slide the mainshaft base over the mainshaft.
h. Attach the mainshaft holder to the mainshaft as follows:
NOTE:
- Back-out the mainshaft holder bolt and loosen the two hex bolts.
- Fit the holder over the mainshaft so its lip is towards the transmission.
- Align the mainshaft holder's lip around the groove at the inside of the mainshaft splines, then tighten the hex bolts.
i. Seat the mainshaft fully by tapping its end with a plastic hammer.
j. Thread the mainshaft holder bolt in until it just contacts the wide surface of the mainshaft base.
k. Zero a dial gauge on the end of the mainshaft.
l. Turn the mainshaft holder bolt clockwise; stop turning when the dial gauge has reached its maximum movement. The reading on the dial gauge is the amount of mainshaft end play.
CAUTION: Turning the mainshaft holder bolt more than 60° after the needle of the dial gauge stops moving may damage the transmission.
m. If the reading is within the standard, the clearance is correct.
If the reading is not within the standard, recheck the shim thickness.
Standard: 0.10 - 0.16 mm (0.004 - 0.006 inch)
TRANSMISSION
Reassembly
1. Install the differential assembly in the clutch housing.
2. Install the spring washer and washer with the angle against the clutch housing as shown.
3. Insert the mainshaft and countershaft into the shift forks, and install them as an assembly.
NOTE: Before installing the mainshaft and countershaft assemblies, tape the mainshaft splines to protect them.
4. Install the reverse idler gear and reverse idler gear shaft in the clutch housing.
5. Install the reverse shift fork in the clutch housing with the 5th/reverse shift piece pin positioned in the slot of the reverse shift fork.
NOTE: Check that the steel ball is in the proper position.
6. Install the oil gutter plate in the transmission housing.
NOTE: Select the 78 mm shim according to the measurements.
7. Install the oil guide plate and 78 mm shim into the transmission housing.
8. Apply liquid gasket to the surface of the transmission housing as shown.
NOTE:
- Use liquid gasket (P/N 08718-0001).
- Remove the dirt and oil from the sealing surface.
- Seal the entire circumference of the bolt holes to prevent oil leakage.
- If 20 minutes have passed after applying liquid gasket, reapply it and assemble the housings. Allow it to cure at least 20 minutes after assembly before filling the transmission with oil.
9. Install the 14 x 20 mm dowel pins.
10. Set the taper cone ring as shown. Place the transmission housing over the clutch housing, being careful to line up the shafts.
11. Lower the transmission housing with the snap ring pliers, and set the snap ring into the groove of the countershaft bearing.
12. Check that the snap ring is securely seated in the groove of the countershaft bearing.
13. Apply liquid gasket (P/N 08718-0001) to the threads of the 32 mm sealing bolt, then install it on the transmission housing.
14. Install transmission hangers A and B, then tighten the bolts in a crisscross pattern in several steps as shown.
15. Install the reverse idler gear shaft bolt.
16. Install the steel balls, springs, washers and setting screws.
17. Install the shift arm cover assembly.
18. Shift the transmission through all the gears before installing it.
OIL SEAL
Installation
1. Install the new oil seal into the transmission housing using the special tools as shown.
2. Install the new oil seal into the clutch housing using the special tools as shown.