DISASSEMBLY
To detect the real cause of trouble, inspect the following items before disassembling.
- Tooth contact and backlash between hypoid driven gear and drive pinion
- Total preload of drive pinion
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- Remove the air breather hose.
- Set the ST on vise and install the differential assembly to ST. ST 398217700 ATTACHMENT SET
- Remove the oil drain plug and filler plug, and drain the gear oil.
- Remove the rear differential oil temperature switch.
- Remove the rear cover by removing retaining bolts.
- Remove the lock plate RH and LH.
- Remove the side retainer RH and LH with the ST. ST 18630AA010 WRENCH COMPLY RETAINER NOTE: Never mix up the RH and LH retainers.
- Pull out the differential case assembly from differential carrier. NOTE: Be careful not to hit the teeth against the case.
- Remove the bearing race from the side retainer RH and LH with the ST and a press. ST 18758AA000 PULLER NOTE: Be sure to turn the bolt of puller manually. Set the side retainer and the puller so that the side retainer claws catch the puller groove.
- Remove the oil seal from the side retainer RH and LH using a screwdriver. NOTE: Perform this operation only when changing oil seal.
- Extract the bearing cone with ST1, ST2 and ST3 NOTE: Do not attempt to disassemble the parts unless necessary. Never mix up the RH and LH bearing races and cones. ST1 498077000 REMOVER ST2 399520105 SEAT ST3 899864100 REMOVER
- Remove the hypoid driven gear by loosening hypoid driven gear bolts.
- Remove the self-locking nut while holding the companion flange with ST. ST 498427200 FLANGE WRENCH
- Extract the companion flange with a puller. ST 399703600 PULLER ASSY
- Removes the drive pinion shaft.
- Remove the rear bearing cone from drive pinion by supporting the cone with ST. NOTE: Place the replacer so that its center-recessed side faces the pinion gear. ST 398517700 REPLACER
- Remove the front oil seal from differential carrier using screwdriver.
- Remove the pilot bearing, front bearing cone and spacer.
- When replacing the bearings, hit out the front bearing cup and rear bearing cup in this order using a brass bar.
ASSEMBLY
Note. Assemble in the reverse order of disassembly. Check and adjust each part during assembly. Use new gaskets and O-rings. Keep the shims and washers in order, so that they are not improperly installed. Thoroughly clean the surfaces on which the shims, washers and bearings are to be installed. Apply gear oil when installing the bearings and thrust washers. Be careful not to mix up the RH and LH bearing races. Replace the oil seals and O-rings with new parts at every disassembly. Apply differential gear oil to the lips when installing the oil seal. Be careful not to mix up the differential oil seal RH and LH.
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- Adjusting preload for front and rear bearings NOTE: Adjust the bearing preload between front and rear bearings with spacer and washer. Pinion height adjusting washer is not affected by this adjustment. The adjustment must not be carried out with oil seal inserted. Install the rear bearing race into the differential carrier using ST1 and ST2. ST1 398477701 HANDLE ST2 398477703 DRIFT 2 Using the ST, install the front bearing race to the differential carrier. ST 499277200 INSTALLER Insert the front bearing cone. NOTE: Use new front bearing cone. Measure and record the thickness of pinion adjust washer. NOTE: If tooth contact (drive pinion, hypoid driven gear) is normal in the inspection before disassembling, verify that the washer is not deformed, and then reuse the used washer. Insert the ST1 into carrier with the pinion height adjusting washer and rear bearing cone fitted onto it. NOTE: Use new rear bearing cone. Install the preload adjusting spacer & washer, front bearing cone, spacer, companion flange, and washer & self-locking nut. ST1 18678AA000 DUMMY SHAFT Turn ST1 by hand to seat the bearing, and measure the initial load and initial torque with a spring scale while tightening the self-locking nut. Select the preload adjusting washer and spacer so that the specified preload is obtained when nut is tightened to the specified torque. NOTE: Use a new self-locking nut. Be careful not to give excessive preload. When tightening the self-locking nut, lock companion flange with ST2 as shown in the illustration. Measure the preload in direction of tangent to the flange. ST1 18678AA000 DUMMY SHAFT ST2 498427200 FLANGE WRENCH Tightening torque: 191 N.m (19.5 kgf-m, 140.9 ft-lb) Initial load: 12.7 - 32.2 N (1.3 - 3.3 kgf, 2.9 - 7.2 lb) Initial torque: 0.48 - 1.22 N.m (0.05 - 0.12 kgf-m, 0.35 0.90 ft-lb) THICKNESS SPECIFICATION Preload adjusting washer Part No. Thickness mm (in) 38336AA430 1.500 (0.0591) 38336AA440 1.513 (0.0596) 38336AA450 1.525 (0.0600) 38336AA460 1.538 (0.0606) 38336AA470 1.550 (0.0610) 38336AA480 1.563 (0.0615) 38336AA490 1.575 (0.0620) 38336AA500 1.588 (0.0625) 38336AA510 1.600 (0.0630) 38336AA520 1.613 (0.0635) 38336AA530 1.625 (0.0640) 38336AA540 1.638 (0.0645) 38336AA550 1.650 (0.0650) 38336AA560 1.663 (0.0655) 38336AA570 1.675 (0.0659) 38336AA580 1.688 (0.0665) 38336AA590 1.700 (0.0669) 38336AA600 1.713 (0.0674) 38336AA610 1.725 (0.0679) 38336AA620 1.738 (0.0684) 38336AA630 1.750 (0.0689) 38336AA640 1.763 (0.0694) 38336AA650 1.775 (0.0699) PRELOAD ADJUSTING SPACER LENGTH SPECIFICATION Preload adjusting spacer Part No. Length mm (in) 31454AA250 51.05 (2.010) 31454AA260 51.25 (2.018) 31454AA270 51.35 (2.022) 31454AA280 51.45 (2.026) 31454AA290 51.55 (2.030) 31454AA300 51.65 (2.033) 31454AA310 51.75 (2.037) 31454AA320 51.85 (2.041) 31454AA330 52.05 (2.049)
- Adjusting drive pinion height: Adjust the drive pinion height with washer installed between the rear bearing cone and the back of pinion gear. Attach the ST2. ST1 18678AA000 DUMMY SHAFT ST2 18831AA010 DIFFERENTIAL CARRIER GAUGE Install the side retainer LH to the left side of the differential carrier in the reverse direction. Measure the clearance "N" between the end of ST2 and the end surface of ST1 by using a thickness gauge. NOTE: Make sure there is no clearance between the case and ST2. ST1 18678AA000 DUMMY SHAFT ST2 18831AA010 DIFFERENTIAL CARRIER GAUGE Obtain the thickness of pinion height adjusting washer to be inserted from the following formula, and replace the temporarily installed washer with this one. NOTE: Adjust it using 0 - 3 washers. T = To + N - 0.05 mm (0.0020 in) THICKNESS SPECIFICATION T Thickness of pinion height adjusting washer mm (in) To Thickness of washer temporally inserted mm (in) N Clearance of thickness gauge mm (in) Memo: (Example of calculation) To = 0.15 mm (0.0059 in) N = 0.1 mm (0.0039 in) T = 0.15 mm (0.0059 in) + 0.1 mm (0.0039 in)-0.05 mm (0.0020 in) = 0.2 mm (0.0079 in) Result: Thickness = 0.2 mm (0.0079 in) Therefore use part number 32295AA370. THICKNESS SPECIFICATION Pinion height adjusting washer Part No. Thickness mm (in) 32295AA350 0.150 (0.0059) 32295AA360 0.175 (0.0069) 32295AA370 0.200 (0.0079) 32295AA380 0.225 (0.0089) 32295AA390 0.250 (0.0098) 32295AA400 0.275 (0.0108)
- Install the selected pinion height adjusting washer on drive pinion, and press the rear bearing cone into position with ST. ST 398177700 INSTALLER
- Insert the drive pinion into the differential carrier, and install the preselected bearing preload adjusting spacer and washer.
- Set ST and differential carrier to the press and install the front bearing cone. ST 399780104 WEIGHT NOTE: Set the carrier to the press until the companion flange is installed.
- Insert the spacer, then install the pilot bearing.
- Fit a new oil seal with ST. NOTE: Press-fit until the oil seal end comes 1 mm (0.04 in) inward from end of carrier. Apply differential gear oil to the oil seal lips. ST 499277200 INSTALLER
- Press-fit the companion flange with ST. NOTE: Be careful not to damage the bearing. ST 899874100 INSTALLER
- Apply seal material to the drive pinion shaft screw threads and on the new self-locking nut seat. Seal material: THREE BOND 1324 (Part No. 004403042) or equivalent
- Attach the nut and use the ST to fix the companion flange in place, then tighten. ST 498427200 FLANGE WRENCH Tightening torque: 191 N.m (19.5 kgf-m, 140.9 ft-lb)
- Measure the initial torque and initial load. Initial load: 12.7 - 32.2 N (1.3 - 3.3 kgf, 2.9 - 7.2 lb) Initial torque: 0.48 - 1.22 N.m (0.05 - 0.12 kgf-m, 0.35 - 0.90 ft-lb)
- Install the hypoid driven gear to differential case. NOTE: Set a cushioning such as wooden block, aluminum plate or shop cloth between vise and differential case if the side gear comes into contact with vise. Before installing bolts, apply seal material to bolt threads. Seal material: THREE BOND 1324 (Part No. 004403042) or equivalent Tighten opposing bolts in order. Tightening torque: 62 N.m (6.3 kgf-m, 45.7 ft-lb)
- Press the side bearing into differential case using ST. ST 398487700 DRIFT
- Assemble the side retainer. Attach the new oil seal to the side retainer RH and LH. ST 498447100 INSTALLER Attach the bearing race to side retainer RH and LH. ST 398417700 DRIFT CAUTION: Make sure that the RH and LH oil seals, bearing outer races and cones are properly assembled. Install the differential assembly into differential carrier in the reverse order of disassembly. NOTE: Be careful so that the teeth do not to hit against the case. Push the side retainer RH and LH lightly into the differential carrier to install.
- Perform the backlash adjustment between the hypoid driven gear and drive pinion, and preload adjustment of differential side bearing. Turn the drive pinion with ST for better fitting of differential side bearing. ST 498427200 FLANGE WRENCH Using the ST, tighten side retainer RH, and then tighten side retainer LH until there is no backlash. ST 18630AA010 WRENCH COMPLY RETAINER Back off the side retainer LH by approx. 1.5 teeth, and tighten the side retainer RH by approx. 2 teeth (amount that the side retainer LH is turned back (1.5) + 1/2 teeth). Difference between [amount that the side retainer LH is turned back (approx. 1 and 1/2 teeth)] and [amount that the side retainer RH is tightened (approx. 2 teeth)] gives preload. Temporarily tighten the lock plate. NOTE: Turn over the lock plate to shift the holder by 1/2 tooth. Measure the hypoid driven gear-to-drive pinion backlash. Set the magnet base on differential carrier. Align the contact point of dial gauge with tooth face of hypoid driven gear, and move hypoid driven gear while holding drive pinion still. Read the value indicated on dial gauge. NOTE: If measured value of backlash is not within the specified range, repeat the procedures for pinion driven gear set backlash adjustment and the differential side bearing preload adjustment. Backlash: 0.10 - 0.15 mm (0.004 - 0.006 in)
- Mark both the differential carrier and side retainer with alignment marks. Remove the side retainer one side at a time. Replace them in the original position after inserting an O-ring and applying differential gear oil to the threaded portion.
- Tighten the bolt of lock plate to specified torque. Tightening torque: 25 N.m (2.5 kgf-m, 18.4 ft-lb)
- Recheck the hypoid driven gear to pinion backlash. Backlash: 0.10 - 0.15 mm (0.004 - 0.006 in)
- Checking and adjusting the tooth contact of hypoid driven gear Apply red lead evenly to the both side of three or four teeth on hypoid driven gear. Check the contact pattern after rotating the hypoid driven gear several revolutions back and forth until a definite contact pattern appears on the hypoid driven gear. When the contact pattern is not correct, readjust. NOTE: Be sure to wipe off the red lead completely after the adjustment is completed. Correct tooth contact Check item: Tooth contact pattern is slightly shifted toward toe side under no-load rotation. (When driving, it moves towards the heel side.) Face contact Check item: Backlash is too large. Contact pattern Corrective action: Increase thickness of drive pinion height adjusting washer in order to bring drive pinion close to hypoid driven gear. Flank contact Check item: Backlash is too small. Contact pattern Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear. Toe contact (inner side contact) Check item: Teeth contact area is too small. Contact pattern Corrective action: Reduce the thickness of pinion height adjusting washer according to the procedure for bringing drive pinion away from hypoid driven gear. Heel contact (outside end contact) Check item: Teeth contact area is too small. Contact pattern Corrective action: Increase thickness of drive pinion height adjusting washer in order to bring drive pinion close to hypoid driven gear.
- If proper tooth contact is not obtained, readjust the drive pinion height, differential side bearing preload (previously described) and the hypoid gear backlash.
- Install the new gasket, rear cover and ground stay to the differential carrier, and tighten the bolts to the specified torque. Tightening torque: 34 N.m (3.5 kgf-m, 25.1 ft-lb)
- Using new gaskets, install the rear differential oil temperature switch. Tightening torque: 60 N.m (6.1 kgf-m, 44.3 ft-lb)
- Affix with the attachment clip so that the white marking of the hose is within the range of Z (87°).