Disassembly
DISASSEMBLY
INSPECTION BEFORE DISASSEMBLY
1. Remove the cover.
2. Hold the special tools MB990909 and MB991116 in a vise, and install the differential carrier assembly to the special tool.
FINAL 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, adjust the final drive gear backlash.
3. After the adjustment, inspect the final 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 runout exceeds the limit value, check for foreign material between drive gear rear side and differential case, or for loose drive gear installation bolts.
3. When step (2) gives normal results, reposition the drive gear and differential case and remeasure.
4. If adjustment is impossible, replace the differential case, or replace the drive gear and pinion as a set.
DIFFERENTIAL GEAR BACKLASH
1. Insert a wedge between the side gear and the pinion shaft to lock the side gear.
2. While locking the side gear with the wedge, measure the differential gear backlash with a dial indicator on the pinion gear. Use the measurement procedure for the other pinion gear.
Standard value: 0 - 0.076 mm (0 - 0.0030 inch)
Limit: 0.2 mm (0.01 inch)
3. If the backlash exceeds the limit value, adjust it by replacing the side gear spacers.
4. If adjustment is not possible, replace the side gears and pinion gears as a set.
FINAL 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 pat tern 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 (22.1 - 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 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 SERVICE POINTS
<> DIFFERENTIAL CASE ASSEMBLY/DIFFERENTIAL SIDE BEARING SPACER/DIFFERENTIAL SIDE BEARING OUTER RACE REMOVAL
CAUTION: When taking out the differential case assembly, be careful not to drop and damage the differential side bearing spacers and differential side bearing outer races.
Use the wooden handle of a hammer to remove the differential case assembly, differential side bearing spacers and differential side bearing outer races.
NOTE: Keep the right and left side bearings and side bearing spacers separate, so that they do not become mixed during reassembly.
<> DIFFERENTIAL SIDE BEARING INNER RACE REMOVAL
Use the special tool MB990810 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 the special tool MB990810 at that position.
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1. Make the mating marks to the differential case and the drive gear.
2. Loosen the drive gear attaching bolts in a diagonal sequence to remove the drive gear.
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Drive out the lock pin with a punch.
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Use the special tool MB990850 to hold the companion flange, and then remove the companion flange self-locking nut.
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CAUTION: The mating mark made on the companion flange must not be on the coupling surface of the companion flange and the front propeller shaft.
1. Make mating marks on the drive pinion and companion flange.
2. Use the special tool MB990810 to pull out the companion flange.
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Use special tools MB990339 and MB990374 to pull out the drive pinion rear bearing inner race.
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Use the special tool MB990939 to remove the oil seal, drive pinion front bearing inner race, and drive pinion front bearing outer race.
<> DRIVE PINION REAR BEARING OUTER RACE REMOVAL
Use the special tool MB990939 to remove the drive pinion rear bearing outer race.