Assembly

Fig. 23 Rear Differential Assembly:

Assemble differential carrier in numbered sequence shown in Figs. 23, noting the following:

Fig. 24 Spring Pin Installation:

1. On models with Four Wheel Steering (4WS), tap spring pin into differential case to position shown in Fig. 24, before press fitting rear wheel oil pump drive gear. Notch on spring should be in position shown.
2. With beveled part of rear wheel oil pump drive gear at inner side, press in drive gear, using rear suspension bushing base tool No. MB990890-01, or equivalent, until drive gear contacts end surface of differential case. Ensure drive gear and spring pin are flush.
3. Press fit drive pinion rear and front bearing outer races onto gear carrier using handle tool and bearing and oil seal installer set tool No. MB990925, or equivalent. Use care not to press in outer race at an angle.
4. Adjust pinion height as follows:

Fig. 26 Pinion Height Adjustment:

a. Install special tools as shown in Figs. 26.

Fig. 28 Pinion Turning Torque:

b. Tighten handle of tool until the standard drive pinion turning torque value shown in Figs. 28 and is obtained.
c. Measure drive pinion turning torque without oil seal installed.
d. Position gauge tube tool No. MB990392-01, or equivalent, in side bearing seat of gear carrier, then select a drive pinion rear shim of thickness which corresponds to gap between special tools.
e. Install selected shim on drive pinion and press fit rear bearing inner race using bearing installer tool No. MT215013, or equivalent.
5. Adjust drive pinion preload as follows:
a. Install drive pinion front shim(s) between pinion spacer and pinion front bearing inner race.
b. Torque companion flange to 135 ft. lbs., using end yoke holder tool to prevent yoke rotation. Do not install oil seal.
c. Ensure drive pinion turning torque is as shown in Figs. 28.
d. If drive pinion turning torque is not within specified range, adjust by replacing drive pinion front shims(s) or drive pinion spacer.
e. Remove companion flange and drive pinion.
f. Install oil seal using suitable oil seal installation tool.
g. Install drive pinion and companion flange aligning marks made during disassemble then tighten companion flange self-locking nut to specification.
h. Measure pinion turning torque with oil seal installed and ensure turning torque is no more than one inch lb. greater than what is shown in Figs. 28.
6. On models with conventional differential, adjust differential gear backlash as follows:
a. Assemble side gears and spacers, pinion gears and washers into differential case.
b. Temporarily install pinion shaft.
c. While locking side gear with wedge, measure differential gear backlash with a dial indicator on pinion gear. The measurement should be made for both pinion gears individually.
d. If differential gear backlash exceeds 0.008 inch, adjust backlash by installing thicker side gear spacers.
e. Measure differential gear backlash again and confirm it is within the specification.
f. After adjustment, ensure backlash is less than limit and differential gear rotates smoothly.
g. When adjustment is impossible, replace side gear pinion gears as a set.
h. Align pinion shaft lockpin hole with differential case and install lockpin.
i. Stake lockpin at two points.
7. Clean drive gear attaching bolts.
8. Use a 10 mmx 1.25 tap to remove adhesive from threaded holes of drive gear.
9. Install drive gear onto differential case aligning marks made during disassemble. Tighten bolts in a diagonal sequence.
10. Press side bearing inner races onto differential case.
11. Adjust final drive gear backlash as follows:
a. Using spanner wrench tool No. MB991367 and pin tool No. MB991385, or equivalents, temporarily tighten side bearing nut until just before preloading.
b. Measure final drive gear backlash at four or more points on drive gear.

Fig. 34 Gear Backlash Adjustment:

c. Using spanner wrench and pin tools, adjust backlash until a 0.004-0.006 inch value is reached by turning side bearing nut as shown, Fig. 34.

Fig. 35 Side Bearing Adjustment:

d. Using the spanner wrench to apply preload, turn down both right and left side bearing nuts on half the distance between centers of two neighboring holes, Fig. 35.

Fig. 36 Bearing Nut Snap Ring Installation:

e. Install snap ring at either position shown to lock side bearing nut, Fig. 36.
f. Check drive gear and pinion tooth contact as outlined under Inspection.
g. Measure drive gear runout at shoulder on reverse side of drive gear.
h. If runout exceeds 0.002 inch, reinstall by changing phase of drive gear and differential case and measure again.
i. Using suitable oil seal installer, install oil seal flush with gear carrier end face.