Rear Differential Service Part 2
REASSEMBLY
1. Install pinion bearing races and baffle plate using outer bearing race installer J-8611-01/inner bearing race installer J-42836 and drive handle J-8592.
NOTE: Baffle plate must be installed, when install the inner pinion bearing race.
2. Clean all the gauge parts.
3. Lubricate the outer and inner bearings with axle lubricant.
4. Place the bearings into the pinion bearing races.
5. Place the inner oil slinger onto the inner pinion bearing.
NOTE: The inner oil slinger must be placed between gauge plate and inner pinion bearing when measuring the pinion depth.
6. Install gauge plate J-39837-2, inner J-42827 stud and nut J-21777-43 and outer pilot J-42824 to the pinion bore.
7. Hold the stud stationary at the flats of the stud (and).
Tighten the stud nut
Torque: 2.2 Nm (1.6 ft. lbs.)
8. Rotate the gauge plate and bearings several complete revolutions to seat the bearings.
9. Tighten the stud nut until a torque of 1.6 to 2.2 Nm (1.2 to 1.6 ft. lbs.) is required to keep the gauge plate in rotation.
10. Assemble discs J-39837-1, arbor J-23597-1 and dial indicator J-8001 to the side bearing bores.
NOTE: The bearing bores must be clean and burr-free.
11. Install the side bearing caps and tighten the bolts to the specified torque.
Torque: 108 Nm (80 ft. lbs.)
12. Rotate the gauge plate until the gauging area is parallel with the discs.
13. Position the arbor assembly in the carrier so that the plunger is centered on the gauge area of the gauge plate.
14. Set the dial indicator to "0". Place it on the mounting post of the gauging arbor with the contact button touching the indicator pad. Force the dial indicator downward until the needle has made a half turn clockwise. Tighten down the dial indicator in this position.
15. Position the plunger on the gauge plate. Move the gauging arbor slowly back and forth and locate the position at which the dial indicator shows the greatest defection. At this point, once again set the dial indicator to "0". Repeat the procedure to verify the "0" setting.
16. After the ZERO setting is obtained, rotate the gauging arbor until the dial indicator rod does not touch the gauging plate. Record the number the dial indicator needle points to.
17. Record the pinion depth code on the head of the drive pinion. The number indicates a necessary change in the pinion mounting distance. A plus number indicates the need for a greater mounting distance (which can be achieved by decreasing the shim thickness). A minus number indicates the need for a smaller mounting distance (which can be achieved by increasing the shim thickness). If examination reveals pinion depth code "0", the pinion is "nominal".
18. Select the shim using the chart;
19. Remove bearing caps and depth gauging tools.
20. Install the correct pinion shim and inner oil slinger onto pinion.
NOTE: Do not install pinion gear into housing at this time.
21. If the exciter ring was removed, install the new exciter ring onto the differential case by pressing using the ring gear as a pilot.
22. Install ring gear (1) to the differential case (2).
23. Install new ring gear bolts.
- Tighten the ring gear bolts alternately in stages, gradually pulling the ring gear onto the differential case.
Tighten the ring gear bolts in sequence
Torque: 108 Nm (80 ft. lbs.)
NOTE: Discard used bolts and install new ones.
SIDE BEARING PRELOAD ADJUSTMENT
1. The side bearing preload adjustment must be made before installing the pinion.
2. The side bearing preload is adjusted by changing the thickness of both the left and right shims equally. This maintain the original backlash.
3. Install master side bearings J-39836 onto the case. Remove all nicks, burrs, dirt etc., from the hubs to allow the master bearings to rotate freely.
4. Assemble the differential case into the housing (less pinion). Install bearing caps and finger tight bolts. Mount a dial indicator with a magnetic base to the housing and indicate on the flange or head of screw. Force the differential assembly as far as possible in the direction towards the indicator. With force still applied, set indicator at zero (O).
NOTE: Dial indicator set should be capable of a minimum travel of 5.08 mm (0.2 inch).
5. Force the differential assembly as far as it will go in the opposite direction. Repeat these steps until the same reading is obtained.
6. RECORD THE READING OF THE INDICATOR. This amount, in shims, will be included in the final assembly shim stack to establish side bearing preload and ring gear and pinion backlash.
7. After marking sure the readings are correct, remove the indicator and differential assembly from the housing.
PINION INSTALLATION
- The bearing cups should have been installed in Pinion Depth Adjustment in this section.
1. Place the shim (1) and inner oil slinger (2) on the pinion gear, then install the pinion inner bearing (3) using installer J-42828.
- Drive the bearing until the bearing cone seats on the pinion shims.
2. Install a new collapsible spacer.
- Lubricate the pinion bearings with axle lubricant.
3. Install pinion to the axle housing.
4. Install outer pinion bearing onto the pinion.
- Hold the pinion forward from inside the case while driving the bearing onto the pinion.
5. Install oil seal slinger.
6. Install pinion oil seal using installer J-37263.
7. Install the pinion flange to the pinion by tapping it with a rawhide hammer until a few threads show through the pinion flange.
8. Install pinion washer and a new nut while holding the pinion flange with flange holder J-8614-01.
- Tighten the nut until the pinion end play is just taken up. Rotate the pinion while tightening the nut to seat the bearings.
Torque: 217 - 678 Nm (160 - 500 Ft. lbs.)
Once there is no end play in the pinion, the preload torque should be checked.
- Remove flange holder J-8614-01. Using an inch-pound torque wrench, check the pinion preload by rotating the pinion with the wrench. Preload should be at 1.0 to 1.6 Nm (8 to 14 inch lbs.) on new bearings, or 0.46 to 0.69 Nm (4 to 6 inch lbs.) for used bearings.
- If the preload torque is below the preloads given above, continue torquing the nut in small increments. Check the preload after each tightening. Each tightening increases the bearing preload by several pounds. If the bearing preload is exceeded, the pinion will have to be removed, and a new collapsible spacer installed.
- Once a preload of 1.0 to 1.4 Nm (8 to 12 inch lbs.) has been obtained, rotate the pinion several times to assure that the bearings have seated. Recheck the preload, and adjust if necessary.
DETERMINATION OF BACKLASH & PRELOAD SHIMS
1. Install master side bearings onto the case.
2. Install differential assembly into the carrier.
3. Install the bearing cap and finger tight bolts.
4. Set up the dial indicator.
5. Force the differential assembly away from the pinion gear until it is completely seated against the cross bore face of the carrier.
6. With force still applied to the differential case, place the tip of dial indicator on a machined surface of the differential case, if available, or on the head of a ring gear screw, and set the indicator at zero (0).
7. Force the ring gear to mesh with the pinion gear. Rock the ring gear slightly to make sure the gear teeth are meshed. Repeat this procedure several times until the same reading is obtained each time. Be sure the indicator reads zero (0) each time the ring gear is forced back into contact with the cross bore face. This reading will be the necessary amount of shims to be placed between the differential case and side bearing cone on the ring gear side.
8. The remaining amount of shims, which is the difference between the overall found in step 6 of Side Bearing Pre-load Adjustment and step (7) above, should be placed on the other side of the differential case, plus additional 0.38 mm (0.015 inch) for obtaining preload and backlash.
9. Place the required amount of shims on each hub as determined in the previous steps and assemble side bearing cone by using installer J-21784 and handle J-8592.
10. Total torque to rotate - Increase of pinion torque to rotate due to differential case assembly shall not exceed 3.4 Nm (30 inch lbs.) divided by the gear ratio.
11. Assembly the spreader J-24385-B and indicator to the carrier as shown in figure. Spread the carrier 0.5 mm (0.02 inch) for differential installation.
CAUTION: Do not spread the carrier over 0.5 mm (0.02 inch).
12. Remove the indicator.
BACKLASH ADJUSTMENT
1. Install the differential case assembly and bearing caps.
2. Rotate the case several times to seat the bearings.
3. Remove the spreader.
4. Install the side bearing cap bolts.
Tighten side bearing cap bolts
Torque: 108 Nm (80 ft. lbs.)
5. Install a dial indicator to the case using a magnetic base.
6. Place the indicator stem at the heel end of a tooth.
- Set the dial indicator so that the stem is in line with the gear rotation and perpendicular to the tooth angle.
7. Check and record the backlash at three points around the ring gear.
- The pinion must be held stationary when checking backlash.
- The backlash should be the same at each point within 0.07 mm (0.003 inch). If the backlash varies more than 0.07 mm (0.003 inch), check for burrs, a distorted case flange, or uneven bolting conditions.
8. Backlash at the minimum lash point measured should be between 0.13 and 0.20 mm (0.005 and 0.008 inch) for all new gear sets.
9. If the backlash is not within specifications, move the ring gear in or out from the pinion by increasing the thickness of one shims, and decreasing the thickness of the other shim by the same amount. This will maintain the correct rear axle side bearing preload.
- Moving 0.05 mm (0.002 inch) worth of shim from one side of the differential to the other will change the backlash adjustment by 0.03 mm (0.001 inch).
10. After obtaining correct tooth contact described in later, install ABS speed sensor.
11. Install the cover with sealant.
Torque: 40 Nm (30 ft. lbs.)
12. Fill the axle lubricant.
GEAR TOOTH PATTERN CHECK
Checking the ring gear to pinion tooth pattern is to be done only after setting up the axle according to the methods in this section. The pattern check is NEVER to be used as an initial check, or instead of checking pinion depth and backlash adjustments. This check is only to be verify the correct adjustment of the gear set after set up.
1. Wipe all oil out of the carrier, and carefully clean each tooth of the ring gear.
2. Use gear marking compound 1052351 or equivalent and apply this mixture 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. Tighten the bearing cap bolts to the specified torque.
4. Expand the brake shoes until a torque of 54 to 68 Nm (40 to 50 ft. lbs.) is required to turn the pinion. A test made without loading the gears will not give a satisfactory pattern. Turn the pinion 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.
5. Observe the pattern on the ring gear teeth and compare this with figure.
ADJUSTMENTS AFFECTING TOOTH CONTACT
Two adjustments can be made which will affect tooth contact pattern: backlash, and the position of the drive pinion in the case. The effects of bearing preloads are not readily apparent on head loaded tooth contact pattern tests; however, these adjustments should be within specifications before proceeding with backlash and drive pinion adjustments.
The position of the drive pinion is adjusted by increasing or decreasing the distance between the pinion head and the centerline of the ring gear.
Decreasing the distance will move the pinion closer to the centerline of the ring gear. Increasing the distance will move the pinion farther away from the centerline of the ring gear.
Backlash is adjusted by means of the side bearing adjusting shims which move the entire case and ring gear assembly closer to, or farther from, the drive pinion. (The adjusting shims are also used to set side bearing preload.)
If the thickness of the right shim is increased (along with decreasing the left shim thickness), backlash will increase.
The backlash will decrease if the left shim thickness is increased (along with a decrease in right shim thickness).
DIFFERENTIAL CASE ASSEMBLY
Disassembled view
Disassembly
1. Remove lock pin using a small drift.
2. Remove the differential shaft by using a soft metal rod and a hammer.
3. Remove pinion mate gear and thrust washer.
4. Remove side gear and thrust washer.
Inspection And Repair
Make necessary correction or parts replacement if wear, damage, corrosion or any other abnormal condition are found through inspection.
Check the following parts.
- Ring gear, pinion gear
- Bearing
- Side gear, pinion mate gear, differential shaft
- Differential case, carrier
- Thrust washer
- Oil seal
Reassembly
1. Install side gear with thrust washer.
2. Install the pinion mate gear with thrust washer by engaging it with the side gears while turning both pinion mate gears simultaneously in the same direction.
3. Install differential shaft.
1. Be sure to install the differential shaft so that it is in alignment with the lock pin hole in the differential case.
4. Install lock pin.
After lock pin installation, stake the case to secure the lock pin.
LOCKING DIFFERENTIAL ASSEMBLY
Disassembled View
Disassembly
1. Place the holder J-39824 into a vise. Position the differential on the holder with the ring gear side down.
2. Remove Lock pin (1) from differential shaft using a punch.
3. Remove Differential shaft (2) using hammer and punch. Place shop towel behind case to prevent differential shaft from dropping out of case.
4. Assemble clutch pack unloading tool.
a. Install cap J-34174-1 to the bottom differential side gear.
b. Install threaded screw cap J-34174-2 to top differential side gear. Thread forcing screws J-22342-15 into threaded screw cap until it becomes centered into the bottom cap.
c. Tighten forcing screw until tight enough to collapse dished spacers and and allow looseness between side and pinion mate gears.
5. Both pinion mate gear thrust washers using a shim stock (1) of 0.51 mm (0.020 inch) or equivalent tool to push out washers.
6. Relieve tension of dished spacers by loosening forcing screw.
NOTE: You may have to adjust the forcing screw slightly to allow the case to rotate.
7. Assemble LSD service adapter J-39834 onto long drive handle J-8592.Insert it into differential shaft hole of case. Pull on handle and rotate case until pinion mate gears can be removed.
8. Remove pinion mate gears.
9. Hold side gear top clutch pack (1) with one hand and remove Positraction unloading tools.
10. Remove top side gear and clutch pack.
NOTE: Keep the stack of plates and discs intact and in exactly the same position while they are being removed.
11. Remove case from holder. Turn case with flange or ring gear side up to allow side gear and clutch pack to be removed from case.
12. Remove differential plate retainer from both clutch packs to allow separation of the plates and discs.
NOTE: Keep the discs and plates in the same order as they were removed.
Inspection And Repair
Cleaning
- All parts with solvent.
Visual Inspection
- Clean all parts with solvent.
- Plates and Discs. If any one disc or plate in either stack shows evidence of excessive wear or scoring, the complete stack is to be replaced on both sides.
- Side Gears and Pinion Mate Gears. The gear teeth of these parts should be checked for extreme wear and possible cracks. The external teeth of the side gear, which retain the concentric groove discs, should also be checked for wear or cracks.
- If replacement of one gear is required due to wear, etc., then both side gears, pinion mate gears, and thrust washers are to be replaced.
- Differential Shaft. If excessive wear is evident, the differential shaft should be replaced.
- Differential Plate Retainers. If wear is evident on any one of the differential plate retainers, all four retainers must be replaced.
- Differential Case. If scoring, wear or metal pickup is evident on the machined surfaces, replacement of the case is necessary.
Reassembly
1. Lubricate thrust face of side gears, plates and discs with the proper limited slip rear axle lubricant.
2. Assemble plates and discs in exactly in the same position as they were removed, regardless of whether they are new or original.
3. Install differential plate retainer to ears of plates.
NOTE: Make sure both retainers are Completely seated on ears of plates.
4. Install clutch pack and side gear into bottom side gear bore. Make sure clutch pack stays assembled to side gear splines, and that retainers are completely seated into pockets of case.
NOTE: To prevent clutch pack from falling out of case, hold clutch pack in place by hand while repositioning case on bench.
5. Install other side gear and clutch pack. Make sure clutch pack stays assembled to side gear splines, and retainers are completely seated into pockets of case.
6. Hold clutch pack in position and assemble screw cap J-34174-2, cap J-34174-1 and forcing screw J-22342-15. Tighten forcing screw into bottom cap to hold both clutch packs in position.
7. With tools assembled to case, position case on holder J-39824 by aligning splines of side gear with those of shaft. Tighten forcing screw to compress clutch packs in order to provide clearance for pinion mate gears.
8. Install pinion mate gears.
- Place the pinion mate gears into the differential 180 degrees apart.
9. While holding gears in place, insert LSD service adapter J-39834 with long drive handle J-8592 in differential shaft hole of case. Pull on long drive handle J-8592 and rotate case, allowing gears to turn. Make sure that holes in pinion mate gears align with holes in case.
- It may be necessary to adjust tension on forcing screw to rotate case.
10. Tighten forcing screw to compress the clutch packs, to allow installation of spherical thrust washers.
11. Lubricate spherical thrust washers (2), and assemble into case (1). Use a small screw driver to push washers into place. Remove tools.
12. Position differential shaft in case and drive in with hammer. Be sure lock pin hole of differential shaft (5) is properly aligned to allow installation of lock pin (3). Be sure that thrust washers and differential pinion mate gears are aligned with the differential case (4). Install new lock pin to proper depth using a punch. Stake metal of case over pin in two places, 180 degrees apart.