Differential Overhaul
DISASSEMBLYPre-inspection
Before disassembling final drive, perform the following inspection.
- Total preload
1. Turn drive pinion in both directions several times to set bearing rollers.
2. Check total preload with Tool.
Tool number: ST3127S000 (See J25765-A)
Total preload: 1.4 - 3.1 Nm (14 - 32 kg-cm, 12 - 28 inch lbs.)
- Ring gear to drive pinion backlash Check ring gear-to-drive pinion backlash with a dial indicator at several points.
Ring gear backlash: 0.10 - 0.15 mm (0.0039 - 0.0059 inch)
- Ring gear runout
Check runout of ring gear with a dial indicator.
Runout limit: 0.05 mm (0.0020 inch)
- Tooth contact
Check tooth contact. Refer to Adjustment.
Differential Carrier
1. Using two 45 mm (1.77 inch) spacers, mount carrier on Tool.
Tool number: KV38100800 ( - )
2. For proper reinstallation, paint or punch matchmarks on one side of the side bearing cap.
Bearing caps are line-board during manufacture. Replace them in their proper positions.
3. Remove side bearing caps.
4. Lift differential case assembly out with Tool.
Tool number: HT72400000 ( - )
Keep the side bearing outer races together with inner cone - do not mix them up. Also, keep side bearing spacer and adjusting shims together with bearings.
5. Loosen drive pinion nut and pull off companion flange.
Tool number: KV38104700 (J34311)
6. Take out drive pinion (together with rear bearing inner race, bearing spacer and adjusting washer).
7. Remove oil seal.
8. Remove front bearing inner race.
9. Remove side oil seal.
10. Remove pinion bearing outer races with a brass drift.
11. Remove pinion rear bearing inner race and drive pinion height adjusting washer with Tool.
Tool number: ST30031000 (J22912-01)
Differential Case
1. Remove side bearing inner cones.
To prevent damage to bearing, engage puller jaws in groove.
Tool number:
(A) ST3305S001 ( - )
(B) ST33061000 (J8107-2)
Be careful not to confuse left- and right-hand parts.
2. Loosen ring gear bolts in a criss-cross fashion.
3. Tap ring gear off the differential case with a soft hammer.
Tap evenly all around to keep ring gear from binding.
4. Loosen screws on differential cases A and B.
5. Separate differential cases A and B.
INSPECTION
Contact Surfaces
1. Clean the disassembled parts in suitable solvent and blow dry with compressed air.
2. If following surfaces are found to be burred or scratched, smooth with oil stone.
- Differential case A
- Differential case B
- Side gear
- Pinion mate gear
- Pinion mate shaft
3. Check viscous coupling for oil leakage. If it is faulty, replace it with new one.
Bearing
1. Thoroughly clean bearing.
2. Check bearings for wear, scratches, pitting or flaking. Check tapered roller bearing for smooth rotation. If damaged, replace outer race and inner cone as a set.
ADJUSTMENT
Differential Case
THRUST WASHER SELECTION
Whenever side gears or pinion mate gears are replaced, select suitable thrust washers as follows:
1. Clean side gears and pinion mate gears using white gasoline.
2. Before assembling gears, apply hypoid gear oil to frictional surfaces.
3. Install the previously removed thrust washer on right side gear. On left side gear, install a suitable thrust washer. Temporarily tighten differential cases using two screws.
4. Position differential assembly so that right side gear is on the upper side. Place two feeler gauges of 0.03 mm (0.0012 inch) thickness between right side gear and thrust washer as shown.
Do not place feeler gauge at groove side of differential case.
5. Also place a 0.03 mm (0.0012 inch) additional feeler gauge between right side gear and thrust washer so that it is positioned diagonal to (180° apart from) the feeler gauge described previously.
6. Rotate right side gear with a suitable tool attached to splines. If hard to rotate, replace thrust washer on left side gear with a thinner one.
7. Replace both 0.03 mm (0.0012 inch) feeler gauges with 0.10 mm (0.0039 inch) gauges. At this point, make sure right side gear does not rotate. If it rotates, replace thrust washer on left side gear with a thicker one to prevent rotation.
8. As explained in above example, select suitable thrust washers to ensure that:
a. Both side gears rotate. [0.03 mm (0.0012 inch) feeler gauges are used in this case.]
b. Side gear is held stationary. [0.10 mm (0.0039 inch) gauges are used in this case.]
For quiet and reliable final drive operation, the following five adjustments must be made correctly.
1. Side bearing preload
2. Pinion gear height
3. Pinion bearing preload
4. Ring gear to pinion backlash. Refer to ASSEMBLY.
5. Ring and pinion gear tooth contact pattern
Side Bearing Preload
A selection of carrier side bearing preload shims is required for successful completion of this procedure.
1. Make sure all parts are clean. Also, make sure the bearings are well lubricated with light oil or DEXRON(TM) type automatic transmission fluid.
2. Place the differential carrier, with side bearings and bearing races installed, into the final drive housing.
3. Put the side bearing spacer in place on the ring gear end of the carrier.
4. Use the J25267 side bearing spacer drift. Place original carrier side bearing preload shims on the carrier end, opposite the ring gear.
Tool number: KV38100600 (J25267)
5. Install the side bearing caps in their correct locations and torque the bearing cap retaining bolts.
Specification: 88 - 98 Nm (9 -10 kg-m, 65 - 72 ft. lbs.)
6. Turn the carrier several times to seat the bearings.
7. Measure the turning torque of the carrier at the ring gear retaining bolts with a spring gauge, J-8129.
Specification: 34.3 - 39.2 N (3.5 - 4 kg, 7.7 - 8.8 lbs.) of pulling force at the ring gear bolt
8. If the turning torque is not within the specifications correct the torque as follows:
- If the turning torque is less than the specified range, install washers of greater thickness.
- If the turning torque is greater than the specification, install thinner washers.
- See Application and ID for washer dimensions and part numbers.
9. Record the total amount of washer thickness required for the correct carrier side bearing preload.
10. Remove the carrier from the final drive housing. Save the selected preload washers for later use during the assembly of the final drive unit.
Tool number: HT72400000 ( - )
Pinion Gear Height and Pinion Bearing Preload
1. Make sure all parts are clean and that the bearings are well lubricated.
2. Assemble the pinion gear bearings into the pinion preload shim selector Tool, J-34309.
- Front pinion bearing-make sure the J-34309-3 front pinion bearing seat is secured tightly against the J-34309-2 gauge anvil. Then turn the front pinion bearing pilot, J-34309-5, to secure the bearing in its proper position.
- Rear pinion bearing - the rear pinion bearing pilot, J-34309-8, is used to center the rear pinion bearing only. The rear pinion bearing locking seat, J-34309-4, is used to lock the bearing to the assembly.
- Installation of J-34309-9 and J-34309-16 - place a suitable 2.5 mm (0.098 inch) thick plain washer between J-34309-9 and J-34309-16. Both surfaces of J-34309-9 and J-34309-16 must be parallel with a clearance of 2.5 mm (0.098 inch).
3. Install the pinion rear bearing inner cone into the final drive housing. Then place the pinion preload shim selector Tool, J34309-1, gauge screw assembly.
4. Assemble the front pinion bearing inner cone and the J34309-2 gauge anvil. Assemble them together with the J34309-1 gauge screw in the final drive housing. Make sure that the pinion height gauge plate, J34309-16, will turn a full 360 degrees. Tighten the two sections together by hand.
5. Turn the assembly several times to seat the bearings.
6. Measure the turning torque at the end of the J-34309-2 gauge anvil using torque wrench J-25765A.
Turning torque specification: 1.0 - 1.3 Nm (10 - 13 kg-cm, 8.7 - 11.3 inch lbs.)
7. Place the J-34309-11 "R200A" pinion height adapter onto the gauge plate and tighten it by hand.
CAUTION: Make sure all machined surfaces are clean.
-PINION BEARING PRELOAD WASHER SELECTION-
8. Place the solid pinion bearing spacer, small end first, over the J34309-2 gauge anvil. Seat the small end squarely against the tip of the J34309-1 gauge screw in the tool recessed portion.
9. Select the correct thickness of pinion bearing preload adjusting washer. Select by using a standard gauge of 3.5 mm (0.138 inch) and your J34309-101 feeler gauge. The exact measure you get with your gauges is the thickness of the adjusting washer required. Select the correct washer from the following chart.
Drive pinion bearing preread adjusting washer: Refer to Application and ID.
10. Set aside the selected correct pinion bearing preload adjusting washer. Use it when assembling the pinion gear and bearings into the final drive.
- PINION HEIGHT ADJUSTING WASHER SELECTION-
11. Now, position the side bearing discs, J-25269-4, and arbor firmly into the side bearing bores. Install the side bearing caps and tighten the cap bolts to proper torque.
12. Select the correct standard pinion height adjusting washer thickness. Select by using a standard gauge of 3 mm (0.12 inch) and your J34309-101 feeler gauge. Measure the distance between the J-34309-11 pinion height adapter including the standard gauge and the arbor.
13. Write down your exact measurement (the value of feeler gauge).
14. Correct the pinion height washer size by referring to the "pinion head number". There are two numbers painted on the pinion gear. The first one refers to the pinion and ring gear as a matched set. This number should be the same as the number on the ring gear. The second number is the "pinion head height number". It refers to the ideal pinion height from standard for quietest operation. Use the following chart to determine the correct pinion height washer.
15. Select the correct pinion height washer from the chart.
Drive pinion height adjusting washer: Refer Application and ID.
16. Remove the J34309 pinion preload shim selector Tool from the final drive housing. Then disassemble to retrieve the pinion bearings.
Tooth Contact
Checking gear tooth contact pattern is necessary to verify correct relationship between ring gear and drive pinion. Hypoid gears which are not positioned in proper arrangement may be noisy and/or have a short life. Check gear tooth contact pattern to obtain the best contact for low noise and long life.
1. Thoroughly clean ring gear and drive pinion teeth.
2. Lightly apply a mixture of powdered ferric oxide and oil or the equivalent. Apply it to 3 or 4 teeth of ring gear drive side.
3. Hold companion flange steady by hand and rotate the ring gear in both directions.
ASSEMBLY
1. Place differential case on ring gear.
2. Apply locking sealant to ring gear bolts, and install them.
Tighten bolts in a criss-cross fashion, lightly tapping bolt head with a hammer.
3. Press-fit side bearing inner cones on differential case with Tool.
Tool number:
(A) KV38100300 (J25523)
(B) ST33061000 (J8107-2)
4. Press-fit front and rear bearing outer races with Tools.
Tool number:
(A) Suitable tool
(B) ST30611000 (J25742-1)
(C) ST30613000 (J25742-3)
5. Select pinion bearing adjusting washer and drive pinion bearing spacer. Refer to ADJUSTMENT.
6. Install selected drive pinion height adjusting washer in drive pinion. Using press and Tool, press-fit pinion rear bearing inner cone into it.
Tool number: ST30901000 ( - )
7. Place pinion front bearing inner cone in final drive housing.
8. Set drive pinion assembly (as shown in figure) in differential carrier and install drive pinion, with press and suitable tool. Stop when drive pinion touches bearing. Apply multi-purpose grease to pinion rear bearing inner race and pinion front bearing inner race.
9. Install front oil seal with Tool.
Tool number: KV38100500 ( - )
10. Install companion flange, and tighten pinion nut to specified torque with Tool. Be certain that threaded portion of drive pinion and pinion nut are free from oil or grease.
Tool number: KV38104700 (J34311)
11. Turn drive pinion in both directions several times, and measure pinion bearing preload.
Tool number: ST3127S000 (See J25765-A)
Pinion bearing preload: 1.1 - 1.4 Nm (11 - 14 kg-cm, 9.5 - 12.2 in lbs.)
When pinion bearing preload is outside specifications, replacement is required for pinion bearing adjusting washer and spacer. Replace with those of different thickness.
12. Select side bearing adjusting washer. Refer to ADJUSTMENT.
13. Install differential case assembly with side bearing outer races into gear carrier.
14. Insert left and right side bearing adjusting washers in place between side bearings and carrier.
15. Drive in side bearing spacer with Tool.
Tool number: KV38100600 (J25267)
Spacer location: Right side
16. Align mark on bearing cap with that on gear carrier and install bearing cap on gear carrier.
17. Install side oil seal.
Tool number: KV38100200 (J26233)
18. Measure ring gear-to-drive pinion backlash with a dial indicator.
Ring gear backlash: 0.10 - 0.15 mm (0.0039 - 0.0059 inch)
- It backlash is too small, adjustment of shim thickness is required. Decrease thickness of left shim and increase thickness of right shim by the same amount. If backlash is too great, reverse the above procedure.
Never change the total amount of shims as it will change the bearing preload.
19. Check total preload with Tool.
Tool number: ST3127S000 (See J25765-A)
When checking preload, turn drive pinion in both directions several times to seat bearing rollers correctly.
Total preload: 1.4 - 2.8 Nm (14 - 29 kg-cm, 12 - 25 inch lbs.)
- If preload is too great, remove the same amount of shim to each side.
- If preload is too small, add the same amount of shim to each side.
Never add or remove a different number of shims for each side. Difference in number of shims will change ring gear to drive pinion backlash.
20. Recheck ring gear to drive pinion backlash. Increase or decrease in thickness of shims will cause change to ring gear to pinion backlash.
- Check whether the backlash varies excessively in different places. Foreign matter may be caught between the ring gear and the differential case causing the trouble.
- The backlash can vary greatly even when the ring gear runout is within a specified range. In that case, replace the hypoid gear set or differential case.
21. Check runout of ring gear with a dial indicator.
Runout limit: 0.05 mm (0.0020 inch)
22. Check tooth contact. Refer to ADJUSTMENT.
23. Install rear cover and gasket.