Differential Assembly Overhaul
DIFFERENTIAL ASSEMBLYInspection
To establish a starting point before disassembly, it is necessary to inspect the following:
- Ring gear backlash
- Total bearing preload
- Gear tooth contact
NOTE:
- Be sure the differential is at room temperature before inspecting.
- Record the results of the preliminary inspections as this information will become helpful during reassembly.
Ring Gear Backlash
1. Remove the 20 mm plug and the oil seal.
2. Secure the differential assembly in a vise using soft jaws.
3. Align a differential carrier rib with the 20 mm plug hole, and install the special tools as shown.
4. Measure the backlash of the ring gear in 3-4 places on the differential carrier using the special tools as shown.
Standard: 0.04 - 0.10 mm (0.002 - 0.004 inch)
The difference among the 3-4 measurements taken must not exceed 0.04 mm (0.002 inch).
5. Remove the pinion collar oil seal by punching two holes in the seal 180° apart. Use the same pry point, and alternate between the two holes to lift the seal as shown.
NOTE: Use a wood block to protect the differential
Bearing Preload
6. Remove the differential case cover and the differential carrier.
7. Use a dial-type torque wrench on the drive pinion to measure the drive pinion bearing preload.
8. Reinstall the differential carrier and the differential case cover, then measure the total bearing preload.
Standard: Tp* + 0.89 - 1.13 Nm (9.1 - 11.5 kgf-cm, 7.90 - 9.98 inch lbs.)
*: Drive pinion bearing preload in step 7.
Gear Tooth Contact
9. Remove the differential case cover and differential carrier. Clean and paint the ring gear teeth lightly and evenly with Prussian Blue (on both sides of each tooth).
NOTE: Loosen the bolts in a crisscross pattern, in several steps.
10. Reinstall the differential carrier and the differential case cover, then torque the bolts in a crisscross pattern, in several steps.
11. Install the special tool as shown. Rotate the ring gear one full turn in both directions while applying resistance to the drive pinion.
12. Remove the differential case cover and the differential carrier, then check the tooth contact pattern.
Disassembly
1. Remove the bolts in a crisscross pattern, in several steps, then remove the differential case cover.
2. Remove the oil seal from the differential case cover.
3. Remove the bearing outer race and the 76 mm thrust shim from the differential case cover by driving them out or by heating the differential case cover to about 212° F (100° C).
CAUTION: Do not reuse the 75 mm thrust shim if the bearing outer race was driven out.
NOTE:
- Do not heat the differential case cover in excess of 212° F (100° C).
- If the bearing outer race was removed by heating, allow the differential cover to cool to room temperature.
- Replace the tapered roller bearing with a new one whenever the bearing outer race is replaced.
4. Remove the breather chamber plate and the oil collect plate.
5. Remove the differential carrier from the differential case.
6. Remove the oil cooler.
7. Raise the locknut tab from the groove of the drive pinion.
CAUTION: Make sure that the tab completely clears the groove to prevent damaging the drive pinion threads.
8. Hold the drive pinion using a 1 1/4" (32 mm) hex bit and socket as shown.
9. Remove the locknut and the spring washer from the drive pinion.
NOTE: The locknut has left-hand threads.
10. Remove the pinion collar and the oil seal, then tap the drive pinion through the tapered roller bearing.
11. Remove the drive pinion, the pinion spacer, and the thrust washers.
12. Remove the tapered roller bearing and 40 mm thrust shim using a press as shown.
13. Remove the bearing outer races, 75 mm thrust shim, and thrust washers by driving them out from behind using the grooves provided or by heating the differential case to about 212° F (100° C).
NOTE: Use care when driving out the bearing outer races to prevent damage to the differential case.
CAUTION: Do not reuse the 75 mm thrust shim and thrust washer if the bearing outer race was driven out.
NOTE:
- Do not heat the differential case in excess of 212° F(100° C).
- If the bearing outer race was removed by heating, allow the differential case to cool to room temperature.
- Replace the tapered roller bearing with a new one whenever the bearing outer race is replaced.
DIFFERENTIAL CARRIER
Tapered Roller Bearing Replacement
1. Remove the tapered roller bearings using a press as shown.
2. Install the tapered roller bearings using the special tools and a press as shown.
Backlash Inspection
1. Remove the tapered roller bearings.
2. Install the left driveshaft and the intermediate shaft in the side gears.
3. Measure the backlash of both pinion gears.
Standard: 0.05 - 0-15 mm (0.002 - 0.006 inch)
Service Limit: 0.30 mm (0 - 012 inch)
If the backlash exceeds the service limit, replace the differential carrier.
Ring Gear Replacement
1. Remove the bolts in a crisscross pattern, in several steps, and remove the ring gear.
2. Install the ring gear by tightening the bolts in a crisscross pattern, in several steps. If the bolts are difficult to tighten, make sure that the ring gear is going on to the differential carrier correctly.
DIFFERENTIAL ASSEMBLY REASSEMBLY
NOTE:
- If replacement is required, always replace the drive pinion and ring gear as a set.
- If the drive pinion and ring gear are replaced, check the height adjustment.
1. Install the 40 mm thrust shim and tapered roller bearing using the special tool and a press as shown.
NOTE: Use a used pinion spacer with the special tool for bearing installation, and then discard the used pinion spacer.
2. Check the differential case bearing surface areas for burrs, and remove as needed. Position the inboard thrust washer into the differential case. Using the sides of the special tools stamped "B", install the inboard bearing outer race as shown. Repeat for the outboard bearing outer race.
a. First install the outboard bearing outer race.
b. Next install the inboard bearing outer race.
3. Install the 75 mm thrust shim and bearing outer race using the special tools as shown.
NOTE: Install the 75 mm thrust shim that was removed.
4. Install the 75 mm thrust shim and bearing outer race using the special tools as shown.
NOTE: Install the 75 mm thrust shim that was removed.
5. Apply lubricant to the tapered roller bearing, then install the drive pinion into the differential case as shown.
NOTE: Do not install the pinion spacer and thrust washers at this time.
6. Apply lubricant to the tapered roller bearing, then install the tapered roller bearing using the special tool, and by holding the drive pinion as shown.
7. Install the pinion collar, spring washer and locknut.
NOTE:
- The locknut has left-hand threads.
- Apply a sufficient amount of lubricant (gear oil and molybdenum disulfide in a mixing ratio of 5:1 to the locknut and the threaded part of the shaft.
8. Hold the drive pinion using a 1 1/4' (32 mm) hex bit and socket as shown, then carefully tighten the pinion locknut until there is no play in the drive pinion.
Torque: 20 Nm (2.0 kgf-m, 14 ft. lbs.)
CAUTION: To avoid damaging the tapered roller bearing, do not overtighten the locknut.
9. Clean and paint the ring gear teeth lightly and evenly with Prussian Blue (on both sides of each tooth).
10. Apply lubricant to the tapered roller bearings, install the differential carrier into the differential case, then install the differential case cover.
11. Install the bolts and tighten in a crisscross pattern, in several steps.
12. Install the special tool as shown. Rotate the ring gear one full turn in both directions while applying resistance to the drive pinion.
13. Remove the differential case cover, and check the tooth contact pattern (heel and toe). Adjust the ring gear tooth contact as needed.
14. After adjusting the ring gear tooth contact, remove the drive pinion, then install a new pinion spacer and thrust washers on the drive pinion.
15. Apply lubricant to the tapered roller bearing, then install it using the special tool while holding the drive pinion as shown.
16. Install a new oil seal using the special tools as shown.
17. Install the pinion collar, spring washer and locknut.
NOTE:
- The locknut has left-hand threads.
- Apply a sufficient amount of lubricant (gear oil and molybdenum disulfide in a mixing ratio of 5:1 to the locknut and the threaded part of the shaft.
18. Hold the drive pinion using a 1 1/4" (32 mm) hex bit and socket as shown.
19. Tighten the locknut to 255 Nm (26 kgf-m, 188 ft. lbs.), and measure the tapered roller bearing preload.
NOTE: Rotate the drive pinion several times to ensure proper tapered roller bearing contact.
If the tapered roller bearing preload exceeds the standard, replace the pinion spacer.
If the tapered roller bearing preload is less than the standard, adjust by tightening the locknut a little at a time, but keep the torque within 255 - 324 Nm (26 - 33 kgf-m, 188 - 239 ft. lbs.). If this is not possible, replace the pinion spacer.
20. Clean and paint the ring gear teeth lightly and evenly with Prussian Blue (on both sides of each tooth).
21. Install the differential carrier into the differential case, and reinstall the differential case cover.
22. Install the bolts and tighten in a crisscross pattern in several steps.
Torque: 47 Nm (4.8 kgf-m, 35 ft. lbs.)
23. Install the special tool as shown. Rotate the ring gear one full turn in both directions while applying resistance to the drive pinion.
24. Remove the special tool, and use a dial-type torque wrench on the pinion shaft to check total bearing preload.
NOTE: Rotate the drive pinion several times to ensure proper bearing contact.
Standard: Pinion and ring gear bearings are new:
Tp* + 1.26-1.57 Nm (12.8 - 16.0 kgf-cm, 11.1 - 13.9 inch lbs.)
Pinion and ring gear bearings are reused:
Tp* + 0.89-1.13 Nm (9.1 - 11.5 kgf -cm, 7.90 - 9.98 inch lbs.)
Ring gear bearing is new:
Tp* + 1.26-1.57 Nm (12.8-16.0 kgf-cm, 11.1 - 13.9 inch lbs.)
Pinion bearing is new:
Tp* + 0.89-1.13 Nm (9-1 -11.5 kgf-cm, 7.90 - 9.98 inch lbs.)
*:Drive pinion bearing preload measured in step 19.
If the total preload is not within the standard, correct it by increasing or decreasing the preload on the carrier bearings as needed. If there is too much preload, decrease the shim thickness equal amounts on both sides. If there is not enough preload, increase the shim thickness equal amounts on both sides.
NOTE: Be sure the same amount of shim thickness is added or subtracted from both sides, so that the backlash and tooth contact pattern are not affected.
25. Secure the differential assembly in a vise using soft jaws.
26. Align a differential carrier rib with the 20 mm plug hole, and install the special tools as shown.
27. Measure backlash in 3-4 places on the differential carrier using the special tools as shown.
Standard: 0.04 - 0.10 mm (0.002 - 0.004 inch)
The difference among the 3-4 measurements taken must not exceed 0.04 mm (0.002 inch).
28. If the backlash is less then the standard, adjust the ring gear backlash .
29. Remove the differential case cover, and check the tooth contact pattern (face and flank). If the tooth contact is not correct, adjust ring gear tooth contact.
30. After all adjustments are made, install the oil collect plate and the breather chamber plate, then stake the screw heads in the groove as shown.
31. Apply liquid gasket to the mating surface of the differential case.
NOTE:
- Use liquid gasket (P/N 08718-0001).
- Remove the dirt and oil from the sealing surface.
- If 20 minutes have passed after applying liquid gasket, reapply it and assemble the housings, and allow it to cure at least 20 minutes after assembly before filling the transmission with oil.
32. Install the differential case cover.
NOTE: Torque the bolts in a crisscross pattern, in several steps.
33. Install the oil seal using the special tools as shown.
34. Install the O-ring and the oil cooler.
35. Stake the locknut tab into the groove.
36. Install the pinion collar oil seal using the special tools as shown.
DRIVE PINION
Height Adjustment
NOTE: If the drive pinion and ring gear are replaced (always as a set), the height has to be adjusted.
Select the proper 40 mm thrust shim as follows:
First, calculate the difference in size between the old shim and the new drive pinion. The last one of the numbers (see illustration.) on each drive pinion is the plus (+) or minus (-) tolerance in thousandths of a millimeter. So, a drive pinion with + 20 is 0.02 mm larger and a drive pinion with - 20 is 0.02 mm smaller.
1. If the number on the old drive pinion is a plus (+ add it to the old shim thickness. If it is a minus subtract it from the old shim thickness.
2. If the number on the new drive pinion is a plus subtract it from the number you got in step 1. If it is a minus (-), add it to the step 1 number.
3. Select the shim that is closest (but not more than) the final number you got from steps 1 and 2.
Example 1:
Old shim: 1.30 mm thickness
Old pinion: + 20 (0.02 mm)
New pinion: - 20 (0.02 mm)
1.30 + 0.02 + 0.02 = 1.34
Select the 1.33 mm (0.0524 inch) new shim.
Example 2:
Old shim: 1.30 mm thickness
Old drive pinion: + 20 (0.02 mm)
New drive pinion: + 40 (0.04 mm)
1.30 + 0.02 - 0.04 = 1.28
Select the 1.27 mm (0.0500 inch) new shim.
RING GEAR TOOTH CONTACT
Adjustment
1. CORRECT TOOTH CONTACT
2. TOE CONTACT
- Use a thinner drive pinion shim (40 mm thrust shim) to move the drive pinion away from the ring gear.
3. HEEL CONTACT
- Use a thicker drive pinion shim (40 mm thrust shim) to move the drive pinion toward the ring gear.
4. FLANK CONTACT
- To move the ring gear away from the drive pinion, use a thicker side bearing shim (75 mm thrust shim) on the drive pinion side and a thinner one on the ring gear side.
NOTE: Recheck backlash after replacing the side bearing shims. If out of specification, adjust as described under TOE CONTACT.
5. FACE CONTACT
- To move the ring gear toward the drive pinion, use a thinner side bearing shim (75 mm thrust shim) on the drive pinion side and a thicker one on the ring gear side.
NOTE: Recheck backlash after replacing the side bearing shims. If out of specification, adjust as described under HEEL CONTACT.
RING GEAR BACKLASH
Adjustment
1. If the backlash exceeds the standard, correct by decreasing the shim thickness on one side and increasing the thickness of the other shim the same amount.
NOTE:
- The total thickness of both shims must still equal the total thickness of the original shims.
- If there is too much backlash, move the ring gear toward the drive pinion. If there is not enough backlash, move the ring gear away from the drive pinion.
2. After adjustment, recheck backlash.
Standard: 0.04 - 0.10 mm (0.002 - 0.004 inch)