Reassembly
This document has been updated by TSB# 09-27-001.
REASSEMBLY
LUBRICATION AND ADHESIVE POINTS
REASSEMBLY SERVICE POINTS
]]A[[ DRIVE PINION REAR BEARING OUTER RACE PRESS-FITTING
Use special tools MB990938, MB990937 [6G72], MB991445 [6G74] to press-fit the drive pinion rear bearing outer races into the gear carrier.
]]B[[ DRIVE PINION FRONT BEARING OUTER RACE PRESS-FITTING
Use special tools MB990938 and MB990934 to press-fit the drive pinion front bearing outer race.
]]C[[ DRIVE PINION HEIGHT ADJUSTMENT
Adjust the drive pinion height by the following procedures:
1. Apply multipurpose grease to the washer of special tool MB990819.
2. Install special tool MB990819, MB991169 and drive pinion front and rear bearing inner races to the gear carrier as shown in the illustration.
3. Tighten the nut of special tool MB990819 a little at a time while measuring the turning torque of the drive pinion. Then confirm that the turning torque (without the oil seal) is at the standard value.
Standard Value:
4. Clean the side bearing hub.
5. Place special tool MB991170 [6G72] or MB991534 [6G74] between the side bearing hub of the gear carrier, and position the notch as shown in the illustration. Then tighten side bearing mounting bolt.
6. Use a feeler gauge to measure the clearance (A) between special tools MB991169, MB991170 and MB991534.
7. Remove special tool MB991169.
8. Use a micrometer to measure the shown dimensions (B,C) of special tools MB991169, MB991170 and MB991534.
9. Install the bearing cap, and then use a cylinder gauge to measure the inside diameter (D) of the bearing cap.
10. Calculate thickness (F) of the required drive pinion rear shim twice by the following formula. Select a shim which most closely matches this thickness. F = A + B + C - 1/2D - E
E: [6G72] 115.00 mm (4.527 inches) [6G74] 120.00 mm (4.724 inches)
11. Fit the selected drive pinion rear shim(s) to the drive pinion, and press-fit the drive pinion rear bearing inner race by using special tool MB990728 [6G72] and MB990802 [6G74].
]]D[[ DRIVE PINION PRELOAD ADJUSTMENT
1. Insert the drive pinion into the gear carrier, and then install the following parts in sequence from the carrier rear side. Drive pinion spacer, drive pinion front shim and drive pinion front bearing inner race, companion flange.
NOTE: Do not install the oil seal.
2. Tighten the companion flange to the specified torque by using special tool MB990850.
Tightening torque: 216 Nm (159 ft. lbs.)
3. Measure the drive pinion turning torque (without the oil seal).
Standard Value:
4. If the drive pinion turning torque is not within the standard value, adjust the turning torque by replacing the drive pinion front shim(s) or the drive pinion spacer.
NOTE: When selecting the drive pinion front shims, if the number of shims is large, reduce the number of shims to a minimum by selecting the drive pinion spacers. Also, select the drive pinion spacer from the following two types.
5. Remove the companion flange and drive pinion again. Then insert the drive pinion front bearing inner race into the gear carrier. Use special tool MB991168 to press-fit the oil seal.
6. Install the drive pinion assembly and companion flange with mating marks properly aligned. Tighten the companion flange self-locking nut to the specified torque using special tool MB990850.
Tightening torque: 216 Nm (159 ft. lbs.)
7. Measure the drive pinion turning torque (with oil seal) to verify that the drive pinion turning torque complies with the standard value.
8. If the turning torque is not within the standard value, check the tightening torque of the companion flange self-locking nut, and the installation of the oil seal.
]]E[[ DIFFERENTIAL GEAR BACKLASH ADJUSTMENT
Adjust the differential gear backlash by the following procedure:
1. Assemble the side gears, side gear thrust spacers, pinion gears, and pinion washers into the differential case.
2. Temporarily install the pinion shaft.
NOTE: Do not assemble the thrust block and lock pin yet.
3. Insert a wedge between the side gear and the pinion shaft to lock the side gear.
4. While locking the side gear with the wedge, measure the differential gear backlash with a dial indicator on the pinion gear.
Standard value: 0.01 - 0.25 mm (0.0004 - 0.0098 inch)
5. Measure by the same procedure for the other pinion gear.
6. If the backlash exceeds the standard value, replace side bearing adjustment spacers.
7. If adjustment is not possible, replace the side gears and pinion gears as a set.
8. Check that the backlash is within the limit value and that the differential gear turns smoothly
]]F[[ LOCK PIN INSTALLATION
1. Align the pinion shaft lock pin hole with the differential case lock pin hole, and drive in the lock pin.
2. Stake the lock pin with a punch on both sides.
]]G[[ DRIVE GEAR INSTALLATION
1. Clean the drive gear attaching bolts.
2. Remove the adhesive adhered to the threaded holes of the drive gear by turning the tap (M10 x 1.25). Clean the threaded holes by applying compressed air.
3. Apply 3M[TM] stud locking 4170 or equivalent to the threaded holes of the drive gear.
4. Install the drive gear onto the differential case with the mating marks properly aligned. Tighten the bolts to the specified torque in a diagonal sequence.
Tightening torque:
[6G72] 78 - 88 Nm (58 - 65 ft. lbs.)
[6G74] 137 - 167 Nm (101 - 123 ft. lbs.)
]]H[[ SIDE BEARING INNER RACE INSTALLATION
Use special tool MB990802 [6G72], MB998812, MD998829 [6G74] to press-fit the side bearing inner eases into the differential case.
]]I[[ BEARING CAP INSTALLATION
Align the mating marks on the gear carrier and the bearing cap, and then tighten the bearing cap.
]]J[[ DRIVE GEAR BACKLASH ADJUSTMENT
Adjust drive gear backlash as follows:
1. Using special tools MB991367 and MB991385, temporarily tighten the side bearing nut to just before preloading of the side bearing.
2. Measure the drive gear backlash.
Standard value: 0.13 - 0.18 mm (0.005 - 0.007 inch)
3. Using special tools MB991367, MB991385, adjust the backlash to standard value by moving the side bearing nut as shown.
NOTE: First loosen the side bearing nut then tighten the side bearing nut the same amount as when it was loosened.
4. Using special tools MB991367, MB991385, to apply the preload, turn down both right and left side bearing nuts on half the distance between centers of two neighboring holes.
5. Choose and install the lock plate (two kinds).
6. Check the final drive gear tooth contact. If poor contact is evident, make adjustment.
7. Measure the drive gear runout.
Limit: 0.05 mm (0.002 inch)
8. When drive gear runout exceeds the limit, remove the differential case and then the drive gears, moving them to different positions and reinstall them.
9. If adjustment is not possible, replace the differential case or drive gear and drive pinion as a set.