Differential Assembly: Service and Repair
DRIVE AXLE DISASSEMBLEDisassembly Procedure
- Tools Required
- J2619-01 Slide Hammer
- J22813-01 Axle Bearing Puller
- J8107-2 Differential Side Bearing Remover Plug
- J22888 Side Bearing Remover
- J8614-01 Companion Flange Holder
- J25320 Rear Pinion Bearing Remover
1. Raise the vehicle. Support the vehicle.
2. Support the axle with a suitable portable safety stand.
3. Remove both brake drums.
4. Remove the axle cover bolts, the cover and the gasket. Drain the axle lubricant.
5. Remove the pinion shaft lock bolt.
6. Remove the pinion shaft.
- Push the axle shaft in towards the center of the differential case.
- Remove the C lock from the end of the axle shaft.
7. Remove the axle shaft from the axle housing.
8. Remove the oil seal, using a special removal tool. Do not to damage the housing.
Important: The tangs of the tool must engage the bearing outer race.
9. Remove the bearing, using J2619-01 and J22813-01.
10. Remove the differential pinion and the side gears.
11. Roll the pinion gears out of the case with the pinion thrust washers.
12. Mark the gears and the differential case left and right when removing the side gears and the side gear thrust washers.
13. Remove the bearing caps and bolts. Mark the caps and the housing left and right.
Notice: When prying the differential case out of the axle housing, be careful not to damage the cover gasket surface. The differential case must be supported when being removed to prevent falling and possible damage.
14. Remove the differential case.
15. Pry the case from the axle housing at the differential window.
16. Remove the bearing outer races, the shims, and the spacers.
17. Mark the races and shims left and right. Place the races and the shims with the bearing caps.
18. Remove the differential side bearings, using J8107-2 and J22888.
- The jaws of J22888 must pull from beneath the bearing cone and not the cage.
19. Remove the left handed threaded ring gear bolts.
Notice: Do not pry the ring gear from the case. This will damage the ring gear and differential case.
20. Remove the ring gear from the differential. Drive the gear off with a brass drift if necessary.
21. Check the differential drive pinion bearing preload.
- If there is no reading, check the drive pinion gear for looseness by shaking the gear.
- When operating the rear axle for an extended period of time with loose bearings or a worn yoke, you will need to replace the ring and pinion gear.
22. Check the pinion assembly for looseness by moving the pinion back and forth. Looseness indicates excessive bearing wear.
23. Remove the pinion flange nut and washer using J8614-01 to hold the pinion flange.
24. Remove the pinion flange using J8614-01.
25. Remove the pinion from the axle housing. . Thread the pinion nut halfway onto the pinion.
- Install the differential cover with two bolts in order to prevent the pinion from falling.
- Drive the pinion out of the housing with a hammer and a drift.
- Remove the pinion and cover.
26. Remove the collapsible spacer from the pinion. Discard the spacer.
27. Remove the outer seal, using a seal removal tool, and the outer pinion bearing.
28. Remove the inner bearing and the shim from the pinion.
29. Press the bearing off of the pinion using J25320.
30. Remove the shim.
31. Remove the drive pinion bearing cups from the axle housing using a hammer and punch in the slots provided. Move the punch back and forth between one side of the cup and the other in order to work the cups out of the housing
DIFFERENTIAL INSPECTION
Carefully and thoroughly inspect all drive unit parts before assembly. Thorough inspection of the drive parts for wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after assembly.
- Inspect the pinion gear shaft for unusual wear.
- Inspect the pinion gear and side gear teeth for wear, cracks, scoring, and spelling.
- Inspect the thrust washers for wear.
- Inspect the fit of the side gears in the differential case.
- Inspect the fit of the side gears on the axle shafts.
- Inspect the differential case for cracks and scoring.
- Inspect all parts for wear. Replace parts as necessary.
PINION AND RING GEAR INSPECTION
Carefully and thoroughly inspect all drive unit parts before assembly. Thorough inspection of the drive parts for wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after assembly.
Important: Ring and pinion gears are matched sets and both are replaced any time a replacement of either is necessary.
- Inspect the pinion and ring gear teeth for cracking, chipping, scoring, and excessive wear.
- Inspect the pinion gear splines for wear.
- Inspect the pinion flange splines for wear.
- Inspect the fit of the pinion gear splines on the pinion flange.
- Inspect the sealing surface of the pinion flange for nicks, burrs, or rough tool marks that could cause damage to the inside diameter of the seal and result in an oil leak.
- Replace all worn or broken parts.
PINION FLANGE RUNOUT MEASUREMENT
- Tools Required
- J35819 Companion Flange Runout Gauge
- J23409 Dial Indicator Extension
- J8001 Dial Indicator Set
1. Place the vehicle on a hoist, allowing free rotation of the rear wheels.
Important: Accurately reference mark the position of all driveline components relative to the propeller shaft and the axles prior to disassembly. These components include the propeller shafts, the drive axles, the pinion flanges and the output shafts. Reassemble components in the exact order as when removed. Follow the specifications, torque values and any measurements made prior to disassembly.
2. Remove the propeller shaft from the pinion flange. Refer to Propeller Shaft Replacement (Rear Propeller Shaft) and Propeller Shaft Replacement (Front Two-Piece Rear) in Propeller Shaft.
3. Secure the propeller shaft up and out of the way minimizing stress on the universal joints.
4. Install J35819 and J8001.
5. Set the dial indicator back to zero. Refer to Propeller Shaft Runout Check in Vibration Diagnosis and Correction.
6. Rotate the pinion flange 360 degrees. Record the highest and the lowest readings and add them together. Mark the pinion flange at the dial indicator tab showing the points of greatest deflection (highest and lowest).
7. If the pinion flange runout is 0.15 mm (0.006 inch) or less, no further action is required.
8. If the pinion flange runout is over 0.15 mm (0.006 inch) but is no greater than 0.38 mm (0.015 inch) and balance weight is at or near the low point of pinion flange runout indicator reading, no further action is required.
- If balance weight is not at or near the low point of pinion flange runout, remove the weight. Reindex the pinion flange until the runout is 0.25 mm (0.010 inch) or less.
- If it is impossible to achieve 0.25 mm (0.010 inch) or less runout, install a new pinion flange and recheck for 0.25 mm (0.010 inch) or less runout. Service replacement pinion flanges are not equipped with balance weights and no weights should be added.
BEARINGS INSPECTION
Carefully and thoroughly inspect all drive unit parts before assembly. Thorough inspection of the drive parts for wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after assembly.
Important: Bearings and cups are matched sets. Replace both bearing and cup when either part requires replacement.
- Oil the bearings. Inspect the bearings for smooth rotation.
- Inspect the bearing rollers for wear.
- Inspect the bearing cups for wear, cracks, and scoring
SHIMS INSPECTION
Carefully and thoroughly inspect all drive unit parts before assembly. Thorough inspection of the drive parts for wear or stress with subsequent replacement of worn parts eliminates costly drive component repair after assembly.
Inspect shims for cracks and chips. Replace damaged shims with a service shim of an equal size.
PINION DEPTH ADJUSTMENT
Installation Procedure
- Tools Required
- J29710 Differential Side Bearing Installer
- J7818 Rear Pinion Bearing Cup Installer
- J7817 Front Pinion Bearing Cup Installer
- J8092 Driver Handle
1. Install the front pinion bearing cups using J29710, J7817, and J8092.
2. Install the rear pinion bearing cups, using J29710, J7818 and J8092.
DEPTH ADJUSTMENT PROCEDURE
- Tools Required
- J21777-40 Rear Pilot Washer
- J21777-42 Front Pilot Washer
- J2177743 Stud Assembly Bolt
- J2177745 Side Bearing Discs
- J23597-1 Arbor
- J23597-11 Gauge Plate
- J8001-1 Dial Indicator Set
1. Clean all the gauge parts.
2. Lubricate the front and rear pinion bearings with axle lubricant.
3. Place the bearings into the pinion bearing cups. Install J21777-40, J21777-42, J21777-43, and J23597-11 into the pinion bore.
4. Hold the stud stationary at the flats of the stud.
Tighten the stud nut to 2.2 Nm (20 inch lbs.).
Notice: Refer to Fastener Notice in Service Precautions.
5. Rotate the gauge plate and bearings several complete revolutions in order to seat the bearings.
6. In order to keep the gauge plate in rotation, torque the stud nut 1.6 - 2.2 Nm (15 - 25 inch lbs.).
7. Assemble J21777-45, J23597-11, and J8001 to the differential bearing bores. The bores must be clean and free of burrs.
8. Install the side bearing caps.
9. Tighten the bolts finger tight.
10. Rotate the gauge plate until the gauging areas are parallel with the discs.
11. Position the gauge shaft assembly in the carrier so that the dial indicator rod is centered on the gauge area of the gauge block.
12. Set the dial indicator at zero. Push the indicator shaft down until the needle rotates approximately 3/4 of a turn clockwise. Tighten the dial indicator in this position.
13. Slowly rotate the gauge shaft back and forth until the dial indicator reads the greatest deflection. This shows when the indicator needle is centered.
14. Set the dial indicator to zero, at the point of greatest deflection. Repeat the rocking action of the gauge shaft to verify the zero reading.
15. Rotate the gauge shaft until the dial indicator rod does not touch the gauge block.
16. Record the actual number on the dial indicator and not the number that represents how far the needle travels. This is the nominal pinion setting.
Example: If the indicator needle moved counterclockwise 1.70 mm (0.067 inch) to a dial reading of 0.84 mm (0.033 inch), record the dial reading of 0.84 mm (0.033 inch) and not 1.70 mm (0.067 inch). The dial indicator should be in the 0.50 - 1.27 mm (0.020 - 0.050 inch) range.
17. All drive pinion gears are manufactured to a nominal depth with no markings. The dial indicator reading is the shim selection.
18. Remove the bearing caps and depth gauging tools.
19. Install the correct pinion shim to the pinion.
DIFFERENTIAL CASE ASSEMBLY
Installation Procedure
- Tools Required
- J25299 Differential Side Bearing Installer
- J8092 Driver Handle
- J8107-2 Differential Side Bearing Remover Plug
1. Lubricate all the parts with axle lubricant.
2. Install the thrust washers to the side gears.
3. Install the side gears to the differential case on the same side in which the parts were removed.
4. Place one pinion gear on the side gear. Rotate the gear until the pinion is exactly opposite the differential opening. Install the pinion gears to the differential without the thrust washers.
5. Rotate the pinion gears into place. Verify the gears line up with the pinion shaft holes.
6. Install the pinion shaft.
7. Install the pinion shaft lock bolt. Apply Loctite (TM) 242.
Tighten the pinion shaft lock bolt to 34 Nm (25 ft. lbs.).
Notice: Refer to Fastener Notice in Service Precautions.
8. Inspect the mating surfaces of the differential case for cleanliness, and that the surfaces are free of burrs.
9. Install the ring gear to the differential case.
10. Install two threaded studs into the ring gear on opposite sides.
11. Place the ring gear on the case. Align the studs with the holes in the case.
12. Install the ring gear bolts. Tighten the ring gear bolts alternately and in stages, gradually pulling the ring gear onto the differential case.
Tighten the ring gear bolts in sequence to 120 Nm (90 ft. lbs.).
13. Install the differential side bearings, using J25299, J8092, and J8107-2.
- In order to protect the differential case, place J8107-2 in the case on the side opposite the bearing installation.
- Drive the bearing onto the case using J25299 and J8092.
14. Install the differential case to the axle housing. Refer to Side Bearing Preload Adjustment.
PINION INSTALLATION
Installation Procedure
- Tools Required
- J5590 Rear Pinion Bearing Cone Installer
- J23911 Pinion Oil Seal Installer
- J8614-01 Pinion Flange Remover
1. Ensure that the bearing cups have been installed. For bearing cup installation, refer to Pinion Depth Adjustment.
2. Install the selective shim between the inner bearing and the shoulder on the gear.
3. Install the pinion bearing using J5590. Drive the bearing on until the cone seats on the pinion shims.
4. Install a new collapsible spacer. Lubricate the pinion bearings with axle lubricant.
5. Install the pinion to the axle housing.
6. Install the outer pinion bearing onto the pinion using tool J5590. When you drive the bearing onto the pinion, hold the pinion forward from inside the case.
7. Install the pinion oil seal using J23911.
8. Install the pinion flange by tapping the flange with a soft-faced hammer until a few threads are shown.
9. Install the pinion washer and nut while holding the pinion flange with tool J8614-01.
10. Tighten the nut until the pinion end play is just taken up. Rotate the pinion while tightening the nut in order to seat the bearings. Once there is no end play in the pinion, check the preload torque.
11. Remove J8614-01. Check the pinion preload by rotating the pinion with an inch pound torque wrench. Preload should be at or below 2.7 - 3.6 Nm (24 - 32 inch lbs.) on new bearings, or 1.0 - 1.4 Nm (8 - 12 inch lbs.) for used bearings.
Notice: Refer to Fastener Notice in Service Precautions.
12. If the preload torque is below the specified values, continue torqueing the nut in small increments. Check the preload after each tightening. Each tighten increases the bearing preload by several pounds. If the bearing preload is exceeded, remove the pinion, and install a new collapsible spacer.
13. Once the specified preload has been obtained, rotate the pinion several times to ensure the bearings have seated. Recheck the preload, and adjust if necessary.
14. Install the differential case. Refer to Backlash Adjustment.
BACKLASH ADJUSTMENT
Adjustment Procedure
1. Install the differential case, the bearing cups, the spacers, and the shims as determined from the side bearing preload adjustment. Refer to Side Bearing Preload Adjustment.
2. Rotate the case several times in order to seat the bearings.
3. Using a magnetic base, install a dial indicator to the case.
4. Place the indicator stem at the heel end of a gear tooth.
5. Set the dial indicator so that the stem is in line with the gear rotation and perpendicular to the tooth angle.
6. Install the differential bearing caps and the bolts.
Tighten the bolts to 75 Nm (55 ft. lbs.).
Notice: Refer to Fastener Notice in Service Precautions.
7. Check and record the backlash at three or four points around the ring gear.
- When checking backlash, hold the pinion stationary.
- The backlash should be the same at each point within 0.05 mm (0.002 inch). If the backlash varies more than 0.05 mm (0.002 inch), check for the following conditions:
- Burrs
- A distorted case flange
- Uneven bolting
8. For all new gear sets, backlash at the minimum lash point measured should be 0.13 - 0.23 mm (0.005 - 0.009 inch).
9. If the backlash is not within specifications, move the ring gear in or out from the pinion by increasing the thickness of one shim, and decreasing the thickness of the other shim an equal amount. This will maintain the correct axle side bearing preload.
Moving 0.05 mm (0.002 inch) of shim from one side of the differential to the other will change the backlash adjustment by 0.03 mm (0.001 inch).
10. When you have correctly adjusted the backlash, remove the bearing caps and the shim packs.
11. Select a shim 0.10 mm (0.004 inch) thicker than the one removed from the left side. Insert this shim between the spacer and the left bearing race.
12. Install the left bearing cap and bolts. Do not tighten.
13. Select a shim 0.10 mm (0.004 inch) thicker than the shim removed from the right side. Insert the shim between the spacer and the right bearing race. Drive the shim into place.
14. Install the right side bearing cap and bolts.
Tighten the bolts to 75 Nm (55 ft. lbs.).
15. Recheck the backlash. Correct as necessary.
GEAR TOOTH CONTACT PATTERN CHECK
Before the final assembly of the differential, a gear tooth contact pattern check should be performed.
A gear tooth contact pattern check is NOT a substitute for adjusting the pinion depth and the backlash. The gear tooth contact pattern check is a final check in order to verify the correct running position of the ring gear and the drive pinion. Any gear sets which are not aligned properly may be noisy and have a short life. With a pattern check, the best contact between the ring gear and the drive pinion for low noise level and long life can be ensured.
GEAR TOOTH TERMS
The side of the ring gear tooth which curves outward, or is convex, is the DRIVE side (4). The concave side is the COAST side (3). The end of the tooth nearest center of the ring gear is the TOE end (2). The end of the tooth farthest away from the center is the HEEL end (1). The toe end of the tooth is smaller than the heel end.
TEST
1. Wipe the oil out of the carrier.
Carefully clean each tooth of the ring gear.
2. Apply gear making compound sparingly to all ring gear teeth using a medium stiff brush.
When properly used, the area of pinion tooth contact will be visible when hand load is applied.
3. Using a torque wrench, apply a load until a torque of 62 Nm (45 ft. lbs.) is required to turn the pinion.
- A test that is made without loading the gears will not give a satisfactory pattern.
- Turn the companion flange with a wrench so that the ring gear rotates one full revolution.
- Then reverse the rotation so that the ring gear rotates one revolution in the opposite direction.
- Excessive turning of the ring gear is not recommended.
4. Observe the pattern on the ring gear teeth. Refer to Gear Tooth Contact Pattern Check in Rear Drive Axle.
ADJUSTMENTS AFFECTING TOOTH CONTACT
There are two adjustments, backlash and pinion depth, which will affect the tooth contact pattern. The effects of the bearing preloads are not easily seen on hand loaded teeth pattern tests. Make the adjustments within specifications before proceeding with the backlash and the drive pinion adjustments.
Adjust the pinion depth and the backlash as necessary, in order to obtain the correct pattern.
The pinion depth is adjusted by increasing or decreasing the shim thickness between the pinion head and the inner race of the rear bearing. The shim is used in the differential in order to compensate for the manufacturing tolerances. Increasing the shim thickness will move the pinion closer to the centerline of the ring gear.
The backlash is adjusted by means of the side bearing adjusting sleeves which move the entire case and the ring gear assembly closer to, or farther from the drive pinion. The adjusting sleeves are also used in order to set side the bearing preload. In order to increase the backlash, turn the left sleeve in and turn the right sleeve out an identical amount. In order to decrease the backlash, turn the right sleeve in and turn the left sleeve out an identical amount.
The contact pattern must be centrally located up and down on the face of the ring gear teeth.
DRIVE AXLE FINAL ASSEMBLY
Installation Procedure
- Tools Required
- J8092 Driver Handle
- J23765 Axle Bearing Installer
- J23771 Axle Shaft Seal Installer
- J23911 Pinion Oil Seal Installer
1. Install the bearing with J23765 and J8092 until the tool bottoms out against the housing shoulder. Lubricate the bearing with axle lubricant.
2. Install the oil seal using J23771 until the seal is flush with the axle tube.
Lubricate the seal lips with axle lubricant.
Important:
^ Do not damage the oil seal.
^ The splines at the end of the axle shaft must engage with the splines of the axle side gear.
3. Install the axle shafts into the axle housing.
4. Install the C locks on the axle shaft.
Pull the axle shaft outward so the C lock seats in the counterbore of the axle side gear.
5. Install the pinion shad through the case and the differential gears. Align the hole in the pinion shaft with the lock bolt hole.
6. Install the pinion shaft lock bolt.
Tighten the lock bolt to 34 Nm (25 ft. lbs.).
Notice: Refer to Fastener Notice in Service Precautions.
7. Install the cover gasket and cover.
Tighten the cover bolts to 27 Nm (20 ft. lbs.).
8. Fill the axle with new lubricant to a level within 9.5 mm (3/8 inch) of the filler plug hole.
Tighten the filler plug to 35 Nm (26 ft. lbs.).