Disassembly
This document has been updated by TSB# 09-27-001.Inspection Before Disassembly
Secure special tool MB990909 in a vice. Install the differential carrier assembly with the attachment. Then carry out the following inspection.
Drive Gear Backlash
1. Place a dial gauge against the end of a drive gear tooth and secure the drive pinion. Then turn the drive gear and take measurements at four places or more to check the backlash.
Standard value:
[4G64] 0.08 - 0.13 mm (0.003 - 0.005 inch)
[6G72,6G74] 0.13 - 0.18 mm (0.005 - 0.007 inch)
2. If the backlash is not within the standard value, adjust the drive gear backlash.
Drive Gear Runout
1. Measure the drive gear runout at the shoulder on the reverse side of the drive gear.
Limit: 0.05 mm (0.002 inch)
2. If the runout exceeds the limit value, check that there is no foreign material between the reverse side of the drive gear and the differential case, or that there is no looseness in the drive gear mounting bolt.
3. If step 2 is normal, change the assembly position of the drive gear and differential case, and then take another measurement.
4. If adjustment is impossible, replace the differential case or the drive gear and drive pinion as a set.
Differential Gear Backlash [Conventional Differential]
1. Tap in a wooden wedge between the side gear and the pinion shaft- and secure one side gear. Then place a dial gauge (with the measuring probe extended) against the pinion gear and measure the backlash.
Standard value:
[4G64] 0.01 - 0.25 mm (0.0004 - 0.0098 inch)
[6G72, 6G74] 0.01 - 0.25 mm (0.0004 - 0.0098 inch)
Check the other pinion gear by the same procedure.
2. If the backlash exceeds the standard, adjust the differential gear backlash.
3. If adjustment is not possible, replace the side gears and pinion gears as a set.
[Differential With Rear Differential Lock]
1. Insert cloth wrapped screwdriver through side of case B and lock side gear [LH] and pinion gear (one piece).
2. Contact dial gauge on pinion gear facing the locked pinion gear and measure backlash within the standard value.
NOTE: Measure two pinion gears.
Standard value: 0.15 - 0.20 mm (0.006 - 0.008 inch)
3. When backlash exceeds the standard value, adjust side gear spacer [LH].
NOTE: If backlash is within the standard value, assure appropriate gear spacer [RH] thickness and assemble differential case assembly.
Drive Gear Tooth Contact
Check the drive gear tooth contact by the following steps.
1. Apply a thin, uniform coat of machine blue to both surfaces of the drive gear teeth.
CAUTION: If the drive gear is rotated too much, the tooth contact pattern will become unclear and difficult to check.
2. Insert special tool MB990939 between the differential carrier and the differential case, and then rotate the companion flange by hand (once in the normal direction, and then once in the reverse direction) while applying a load to the drive gear, so that the revolution torque [approximately 2.5 - 3.0 Nm (22 - 27 inch lbs.)] is applied to the drive pinion.
3. Check the tooth-contact condition of the drive gear and drive pinion.
NOTE: Checking the tooth contact pattern is the way to confirm that the adjustments of the pinion height and backlash have been done properly Continue to adjust the pinion height and backlash until the tooth contact pattern resembles the standard pattern. If, even after adjustments have been made, the correct tooth contact pattern cannot be obtained, it means that the drive gear and the drive pinion have become worn beyond the allowable limit. Replace the gear set.
DISASSEMBLY
[Vehicles Without Rear Differential Lock]
CAUTION: Do not disassemble the limited slip differential case assembly.
[Vehicles With Rear Differential Lock]
Disassembly Service Points
[A] Side Bearing Nut Removal
Use special tools MB991367 and M139911385, remove the side bearing nut.
NOTE: Keep the right and left side bearings and side bearing nuts separate, so that they do not become mixed at the time of assembly.
[B] Differential Case Assembly Removal
Use the handle of a hammer to remove the differential case assembly.
NOTE: Keep the right and left side bearings and side bearing outer race separate, so that they do not become mixed at the time of assembly.
[C] Side Bearing Inner Race Removal
Use special tools MB990810, MB990811 [4G64, 6G72] and MB991407 [6G74] to pull out the side bearing inner race.
NOTE: Attach the prongs of special tools MB990810, M8990811 [4G64, 6G72] and MB991407 [6G74] to the inner race of the side bearing through the openings in the differential case.
[D] Drive Gear Removal
1. Make mating marks to the differential case and the drive gear.
2. Loosen the drive gear attaching bolts in diagonal sequence to remove the drive gear.
[E] Lock Pin Removal
Drive out the lock pin with a punch.
[F] Self-Locking Nut Removal
Use special tool MB990767 to hold the companion flange, and then remove the companion flange self-locking nut.
[G] Drive Pinion Assembly Removal
CAUTION: Do not make mating marks on the contact surfaces of the companion flange and propeller shaft.
1. Make the mating marks to the drive pinion and companion flange.
2. Drive out the drive pinion together with the drive pinion spacer and drive pinion front shims.
[H] Drive Pinion Rear Bearing Inner Race Removal
Use special tools M13990339, MB990648 [4G64, 6G72] and MD998801 [6G74] to pull out the front bearing inner race.
[I] Oil Seal/Drive Pinion Front Bearing Inner Race/Drive Pinion Front Bearing Outer Race Removal
Use special tool MB990939 to remove drive pinion front bearing outer race.
[J] Drive Pinion Rear Bearing Outer Race Removal
Use special tool MB990939 to remove the drive pinion rear bearing outer race.