Differential Assembly: Service and Repair

Fig. 14 Disassembling Rear Differential. Galant, Eclipse & Expo:

Fig. 15 Disassembling Rear Differential. 3000GT:

Fig. 16 Removing Differential Case:

Fig. 17 Removing Side Bearing:

Disassemble differential assembly in numbered sequence shown in Figs. 14 and 15, noting the following:
1. Perform INSPECTION BEFORE DISASSEMBLY procedure.
2. On except 3000GT models, proceed as follows:
a. Slowly and carefully pry out differential case assembly using hammer handles, Fig. 16. When removing differential case assembly, use caution to ensure that side bearing outer race is not dropped. Keep right and left side bearing separate.
b. Pull out side bearing inner races by using insert tool No. MT303173, pinion carrier bearing puller tool No. MB990339-01 and side bearing cup remover step plate tool No. MB990811-01, or equivalent, Fig. 17.
c. Scribe alignment marks on differential case and drive gear. Loosen drive gear bolts in diagonal sequence to remove drive gear.
d. Drive out lockpin with a punch and remove pinion gears and washers, side gears and spacers.
e. Using end yoke holder tool MB990767-01 or equivalent, remove companion flange self-locking nut.
f. Scribe alignment marks on drive pinion and companion flange. Remove out drive pinion together with drive pinion spacer and shims. Marks should not be made on contact surfaces of companion flange and shaft.
g. Pull out drive pinion bearing inner races by using insert tool, pinion carrier bearing puller tool, and side bearing cup remover step plate tool or equivalent.
h. Drive out drive pinion front and rear bearing from gear carrier.
3. On 3000GT models, proceed as follows:
a. Using spanner wrench tool No. MB991367 and pin tool No. MB991385 or equivalent, remove side bearing nut.
b. Using a suitable press, push differential case until it is pressed against the carrier.
c. Remove differential case from press. Insert two spacers in diagonally opposite positions between side bearing outer race to be removed and inner race. Using a press, remove outer race. Do not allow side bearing to drop. Keep right and left bearings separate. Use a spacer 1.18 inches long, .39 inch wide and .04-.08 inch high made of copper to prevent damage to bearings.
d. Pull out side bearing inner races by using insert tool No. MT303173, pinion carrier bearing puller tool No. MB990339-01 and side bearing cup remover step plate tool No. MB990811-01, or equivalent, Fig. 17.
e. Scribe alignment marks on differential case and drive gear. Loosen drive gear bolts in diagonal sequence to remove drive gear.
f. Using end yoke holder tool MB990767-01 or equivalent, remove companion flange self-locking nut.
g. Scribe alignment marks on drive pinion and companion flange. Remove out drive pinion together with drive pinion spacer and shims. Marks should not be made on contact surfaces of companion flange and shaft.
h. Pull out drive pinion bearing inner races by using insert tool, pinion carrier bearing puller tool, and side bearing cup remover step plate tool or equivalent.
i. Drive out drive pinion front and rear bearing from gear carrier.

ASSEMBLY

Fig. 18 Assembling Rear Differential. Galant, Eclipse & Expo:

Fig. 19 Assembling Rear Differential. 3000GT:

Fig. 20 Installing Spring Pin. Models W/4WS:

Assemble differential carrier in numbered sequence shown in Figs. 18 and 19, noting the following:
1. On except 3000GT models, using oil seal installer tool No. MB991115 and handle tool No. MB990938-01 or equivalent, apply grease to oil seal lip then press fit oil seal until it is flush with end of gear carrier.
2. On 3000GT models w/Four Wheel Steering (4WS), tap spring pin into differential case to position shown in Fig. 20, before press fitting rear wheel oil pump drive gear. Notch on spring should be in position shown.
3. On 3000GT models, 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 that drive gear and spring pin are flush.
4. On all models, press fit drive pinion rear and front bearing outer races onto gear carrier using handle tool and bearing and oil seal installer tool set No. MB990925 or equivalent. Use care not to press in outer race at an angle.
5. Adjust pinion height as follows:

Fig. 21 Adjusting Pinion Height. Galant, Eclipse & Expo:

Fig. 22 Adjusting Pinion Height. 3000GT:

Fig. 23 Pinion Turning Torque. Galant, Eclipse & Expo:

Fig. 24 Pinion Turning Torque. 3000GT:

a. Install special tools as shown in Figs. 21 and 22.
b. Tighten handle of tool until the standard value shown in Figs. 23 and 24, of drive pinion turning torque 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 beat 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.
6. Adjust drive pinion preload as follows:
a. Install drive pinion front shim(s) between pinion spacer and pinion front bearing inner race.
b. Tighten companion flange to specification using end yoke holder tool. Do not install oil seal.
c. Ensure drive pinion turning torque is as shown in Figs. 23 and 24.
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 disassembly then tighten companion flange self-locking nut to specification.
h. Measure pinion turning torque with oil seal installed and ensure that turning torque is no more than one inch lb. greater than what is shown in Figs. 23 and 24.
7. 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 .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 that the backlash is less than limit and differential gear rotates smoothly.
g. When adjustment is impossible, replace side gear pinion hears as a set.
8. On models with conventional differential, align pinion shaft lockpin hole with differential case and install lockpin.
9. Stake lockpin at two points.
10. On all models, clean drive gear attaching bolts.
11. Use an 10mm x 1.25 tap to remove adhesive from threaded holes of drive gear.
12. Install drive gear onto differential case aligning marks made during disassembly. Tighten bolts in a diagonal sequence.
13. Press side bearing inner races onto differential case.
14. On except 3000GT models, adjust final drive gear backlash as follows:
a. Install side bearing spacers, which are thinner than those removed, and mount the differential case assembly into the gear carrier.
b. Push differential case to one side and measure clearance between gear carrier and side bearing.
c. Measure thickness of side bearing spacers on one side, select two pairs of spacers which correspond to thickness plus one half of clearance plus .002 inch. Install one pair each to drive pinion side and drive gear side.
d. Install side bearing spacers and differential case assembly into gear carrier.
e. Tap side bearing spacers with a suitable brass bar to fit them to side bearing outer race.
f. Align marks made during disassembly then tighten bearing cap.
g. With drive pinion locked in place, measure final drive gear backlash.

Fig. 25 Adjusting Gear Backlash. Galant, Eclipse & Expo:

h. If backlash is not .004-.006 inch, change bearing spacers as shown in Fig. 25 to obtain correct backlash.
i. Check tooth contact as outlined under INSPECTION BEFORE DISASSEMBLY.
j. Measure drive gear runout at shoulder on reverse side of drive gear.
k. If runout exceeds .002 inch, reinstall by changing phase of drive gear and differential case and remeasure.
15. On 3000GT models, adjust final drive gear backlash as follows:
a. Using spanner wrench tool No. MB991367 and pin tool No. MB991385 or equivalent, temporarily tighten side bearing nut until just before preloading.
b. Measure final drive gear backlash at four or more points on drive gear.

Fig. 26 Adjusting Gear Backlash. 3000GT:

Fig. 27 Adjusting Side Bearing. 3000GT:

Fig. 28 Installing Bearing Nut Snap Ring. 3000GT:

c. Using spanner wrench and pin tools, adjust backlash until a .004-.006 inch value is reached by turning side bearing nut as shown, Fig. 26.
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. 27.
e. Install snap ring at either position shown to lock side bearing nut, Fig. 28.
f. Check drive gear and pinion tooth contact as outlined under INSPECTION BEFORE DISASSEMBLY.
g. Measure drive gear runout at shoulder on reverse side of drive gear.
h. If runout exceeds .002 inch, reinstall by changing the phase of drive gear and differential case, and remeasure.
i. Using suitable oil seal installer, install oil seal flush with gear carrier end face.