Differential Assembly: Testing and Inspection

Fig. 9 Measuring Final Drive Gear Backlash:

Fig. 10 Measuring Drive Gear Runout:

Fig. 11 Measuring Differential Gear Backlash:

With differential carrier assembly properly supported, perform the following inspections:
1. Measure final drive gear backlash, as follows:
a. With drive pinion locked into place, measure final drive gear backlash using a suitable dial indicator, Fig. 9.
b. Measure at four points or more in the circumference on the drive gear and ensure backlash is .004-.006 inch.
2. Measure gear runout as follows:
a. Measure drive gear runout at the shoulder on reverse side of drive gear, Fig. 10.
b. Ensure runout is a maximum of .002 inch.
3. Measure differential gear backlash as follows:
a. While locking side gear with wedge, measure differential gear backlash with a suitable dial indicator on pinion gear, Fig. 11.
b. Ensure backlash is within the 0-.003 inch limit.
4. Inspect final drive gear tooth contact as follows:
a. Apply a thin, uniform coat of machine blue to both surfaces of the drive gear teeth.

Fig. 12 Inspecting Tooth Contact:

Fig. 13 Differential Carrier Tooth Contact:

b. Insert a brass rod between differential carrier and differential case then rotate companion flange by hand once in each direction while applying a load to the drive gear, so that revolution torque of approximately 28-32 inch lbs. is applied to drive pinion, Fig. 12.
c. Check tooth contact condition of drive gear and pinion, Fig. 13.