Assembly & Adjustment

Coat hypoid gear oil on the sliding surfaces and rotating portions of the gears, bearings, and shafts differential before assembling these parts.

Fig. 12 Exploded View Of 6.38 Inch Differential. Corolla AWD:

Fig. 13 Side Gear Thrust Washer Identification. Corolla AWD:

1. Assemble 2 pinion type differential case as follows:
a. Assemble side gears and thrust washers, with oil groove side positioned toward side gear, into differential case, Figs. 12 and 13.
b. Assemble differential pinions, and insert pinion shaft with straight pin holes aligned. Install the straight pin after completing the side gear backlash adjustment.
2. Assemble 4 pinion type differential case as follows:
a. Assemble side gears and thrust washers, with oil groove side positioned toward side gear, into differential case, Fig. 12.
b. Assemble differential pinions and pinion shaft holder, and insert pinion shafts.
c. Align match marks verified at disassembly, and install case cover on differential case.
d. Tighten differential case cover bolts to 20.3-25.3 ft. lbs. The three long bolts are used to secure the pinion shafts.
3. Adjust differential side gear backlash.
a. Place dial gauge spindle against side gear tooth tip, and while holding one pinion fixed, measure backlash by moving side gear, Fig. 3. Backlash should be .0008-.0059 in. for 6 in. axle, .0008-.0079 in. for 6.38 in. axle and .0020-.0079 in. for 6.7 in. axle.

Fig. 3 Differential Side Gear Backlash Measurement:

b. If the backlash is not within specified limits, disassemble and after selecting proper side gear thrust washer from Fig. 13, reassemble.
4. On 6 and 6.7 inch axle, drive in the straight pin from the ring gear mounting surface side, and peen the case pin hole with a hammer.
5. On all models, press the differential side bearings into case.
6. Install ring gear on differential case as follows:
a. Cut off hexagon head from a separate ring gear set bolt, form a screwdriver slot on the cut end, then screw bolt into gear to serve as guide pin for the ring gear.
b. Heat ring gear to around 90° to 110°C (194° to 230°F), and quickly fit it into case.
c. Install bolts over lock plates. Torque bolts to 66.5-76 ft. lbs. on 6 and 6.7 in. axle and 50.6-57.9 ft. lbs. on 6.38 in. axle.
d. Lock bolts by prying up lock plate lips.
7. Install plate washer on pinion, then press on rear bearing.
8. Mount pinion assembly in case, then install front bearing and companion flange on pinion shaft. Bearing spacer, oil slinger and seal are installed after assembly adjustments have been performed.
9. Press companion flange onto pinion shaft with SST 09557-22022 or equivalent, then install washer and pinion nut.

Fig. 6 Preload (rotating Torque) Measurement:

10. Hold companion flange with tool and tighten pinion nut to obtain specified preload. To prevent bearing damage, tighten pinion nut in small increments, checking preload with torque wrench between each adjustment, Fig. 6.
11. Install differential case on carrier.
a. Assemble differential case, together with bearing cups, on carrier.
b. Assemble adjusting nuts, making sure to fit threads on properly.
c. Assemble bearing caps, and tighten bolts until spring washers just begin to take effect.
d. Screw in adjusting nuts at both sides with tool No. SST-09504-00010 until bearing cups are properly seated in carrier.
e. Tighten adjuster nut opposite ring gear face until ring and pinion backlash is approximately 0.008 inch, then tighten nut on gear face side and recheck backlash. If tightening adjuster nut increases backlash, loosen nut until backlash is eliminated.

Fig. 7 Differential Bearing Preload Adjustment. Models w/removable Carrier:

f. Mount dial indicator with pointer bearing against race as shown in Fig. 7.
g. Adjust case assembly for zero preload by tightening adjuster on gear face side until indicator pointer just begins to move, then tighten nut an additional 1 to 1-1/2 notches from zero preload position.

Fig. 8 Ring Gear & Pinion Backlash Adjustment. Models w/removable Carrier:

h. Adjust ring gear and pinion backlash, Fig. 8, to 0.0039-0.0059 inch on 6 inch axles, or 0.0051-0.0071 inch on 6.38 and 6.7 inch axles, turning both adjusters equal amounts in opposite directions. Adjusters must be turned equally to maintain bearing preload.
i. Torque bearing cap bolts to 40-47 ft. lbs. on 6 inch axle, 43 ft. lbs. on 6.38 inch axle or 54-63 ft. lbs. on 6.7 inch axle, then ensure backlash is still within specifications.
j. Measure total assembly preload by rotating pinion with a torque wrench, Fig. 6. If total preload is not 1.7-3.5 inch lbs. greater than pinion preload set in step 10, recheck differential case installation.
12. Coat several ring gear teeth at 3 evenly spaced positions with lead marking compound.

Fig. 9 Ring Gear & Pinion Tooth Contact Inspection:

13. Hold companion flange firmly to place drag on assembly, rotate ring gear in both directions, then check gear tooth contact pattern, Fig. 9.
14. Remove differential and pinion assemblies from carrier.
15. If tooth contact is incorrect, replace washer between rear bearing and pinion with one that will provide proper tooth contact, Fig. 14. If pinion depth adjustment is necessary, repeat steps 7-15 until proper tooth contact is obtained.
16. Install selected washer and press rear bearing onto pinion, then mount pinion assembly in carrier.
17. Install new bearing spacer, front bearing and oil slinger on pinion.

Fig. 11 Pinion Seal Installation:

18. Using a suitable driver, Fig. 11, install pinion seal to the following depth:
a. 6 inch, recessed 0.039 inch.
b. 6.38 inch, recessed up to 0.02 inch.
c. 6.7 inch, recessed 0.16 inch.

Fig. 5 Companion Flange Replacement:

19. Install companion flange with SST 09557-22022, Fig. 5.
20. Install washer and new pinion nut, hold companion flange and torque nut to 69 ft. lbs. on 6 inch differential, or 80 ft. lbs. on 6.38 and 6.7 inch differentials.

Fig. 6 Preload (rotating Torque) Measurement:

21. Check preload, Fig. 6. If preload is greater than specified, replace bearing spacer. If preload is less than specified, continue tightening nut, 5-10° at a time, until specified preload is obtained. If maximum torque of 174 ft. lbs. is exceeded, replace bearing spacer and repeat procedure. Do not back-off on nut to reduce torque or preload.
22. Ensure lateral and radial runout of companion flange is less than 0.004 inch, then stake shoulder of pinion nut.
23. Install differential assembly and adjust backlash and bearing preload as outlined in step 11.
24. Ensure total assembly preload is within specifications, then install adjusting nut locks.