Disassembly

DISASSEMBLY

DISASSEMBLY SERVICE POINTS
[[A]] INSPECTION BEFORE DISASSEMBLY
1. Remove the cover and gasket.





2. Hold special tools MB990909 and MB99116 in a vise, and install the differential carrier assembly to it.

DRIVE GEAR BACKLASH





1. With the drive pinion locked in place, use a dial gauge to measure the drive gear backlash in four or more places on the drive gear.
Standard value: 0.11 - 0.16 mm (0.004 - 0.006 inch)
2. If the backlash is not within the standard value, insert side bearing adjustment spacers, and then inspect the drive gear tooth contact.

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. When the runout exceeds the limit value, check for foreign material between drive gear rear side and differential case, and for loose drive gear installation bolts.
3. When check (2) gives normal results, reposition drive gear and differential case and remeasure.
4. If adjustment is impossible, replace differential case, or replace drive gear and pinion as a set.

DIFFERENTIAL GEAR BACKLASH





1. While locking the side gear with the wedge, measure the differential gear backlash with a dial indicator on the pinion gear.
Standard value: 0 - 0.076 mm (0 - 0.0030 inch)
Limit: 0.2 mm (0.08 inch)
2. Repeat the same procedure for both pinion gears.
3. If the backlash exceeds the limit, adjust by using the side gear thrust spacers.
4. If adjustment is impossible, replace the side gear and pinion gear as a set.

DRIVE GEAR TOOTH CONTACT
Check the tooth contact of drive gear by following the 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 [approximate 2.5 - 3.0 Nm (22.1 - 26.6 inch lbs.)] is applied to the drive pinion.





3. Check the tooth contact condition of the drive gear and drive pinion.

NOTE: Check the tooth contact pattern 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.

[[B]] DIFFERENTIAL CASE ASSEMBLY REMOVAL





CAUTION: When taking out the differential case assembly, be careful not to drop and damage the side bearing outer races.

NOTE: Keep the right and left side bearings and side bearing adjusting spacers separate, so that they do not become mixed during assembly.

[[C]] SIDE BEARING INNER RACE REMOVAL





Use special tools MB990810, MB990811 to pull out the side bearing inner races.

NOTE: There are two notches provided (at the differential case side) for the claw part of the special tools; use special tools MB990810, MB990811 at that position.

[[D]] DRIVE GEAR REMOVAL





1. Make the 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 the special tool MB990767 to hold the companion flange, and then remove the companion flange self-locking nut.

[[G]] DRIVE PINION ASSEMBLY REMOVAL





CAUTION: The mating mark made on the companion flange must not be on the coupling surface of the flange yoke and the front propeller shaft.

1. Make mating marks on the drive pinion and companion flange.
2. Drive out the drive pinion together with the drive pinion spacer and drive pinion shims.

[[H]] DRIVE PINION FRONT BEARING INNER RACE REMOVAL





Use special tools MB990339, MB990648 to pull out the front bearing inner race.

[[I]] DRIVE PINION REAR BEARING OUTER RACE REMOVAL





Use special tool MB990939 to remove the drive pinion rear bearing outer race.

[[J]] DRIVE PINION FRONT BEARING OUTER RACE REMOVAL





Use special tool MB990939 to remove the drive pinion front bearing outer race.

[[K]] OIL SEAL REMOVAL





Use special tool MB990590 to remove the oil seal.