Differential Case Bearing Preload And Gear Backlash

Fig 1: Adjuster Locks & Bolts

Courtesy of CHRYSLER GROUP, LLC

Backlash is adjusted by moving the adjusters in and out or both. By moving the adjusters the case/ring gear will move closer or further away from the pinion. In most cases this adjustment can be used to achieve the correct gear tooth pattern and set the case bearing preload.

1. Remove adjuster lock bolts (3) and adjuster locks (2).
2. Loosen  the differential bearing caps (4).
3. Slide differential case toward the pinion gear until the gears make contact/zero backlash. If zero backlash cannot be obtained, turn the pinion side adjuster until zero backlash is obtained.
   Fig 2: Adjuster Wrench

   Courtesy of CHRYSLER GROUP, LLC
4. Holding the differential case (2) toward the pinion gear, turn bearing adjusters with Adjuster Wrench (special tool #8883A, Wrench, Differential Adjusting) (1) until adjuster makes contact with the differential bearings/cups.
5. Back off the ring gear side adjuster 4 holes, to obtain initial ring gear backlash.
6. Install ring gear side adjuster lock and bolt. Do not tighten  adjuster lock bolt at this time.
7. Tighten pinion gear side adjuster firmly against the differential case bearing cup.
8. Rotate the pinion several times to seat the differential bearings.
9. Loosen pinion gear side adjuster until it is no longer in contact with the bearing cup, then tighten it until it makes contact.
10. Tighten pinion gear side adjuster an additional:
    • New Bearings:  6 Adjuster Holes
    • Original Bearings:  4 Adjuster Holes
11. Install pinion gear side adjuster lock and bolt.
12. Tighten bearing cap bolts to the proper specification. Refer to SPECIFICATIONS .
13. Tighten adjuster lock bolts to the proper specification. Refer to SPECIFICATIONS .
    Fig 3: Measuring Ring Gear Backlash

    Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    Backlash measurement should not vary more than 0.05 mm (0.002 in) between measuring points. If measurement does vary inspect the gears for burrs, the differential case flange and ring gear mounting.

14. Measure ring gear backlash with a Dial Indicator (special tool #C-3339A, Set, Dial Indicator) (1) and Pilot Stud (special tool #L-4438, Dial Indicator Post) at eight points around the drive side of the ring gear (2). The backlash should be 0.08-0.25 mm (0.003-0.010 in) with a preferred backlash of 0.13-0.18 mm (0.005-0.007 in).
15. Measure Total Torque To Rotate (TTTR) with an inch pound torque wrench. Total Torque To Rotate is:
    • New Bearings:  3.4 - 5.6 N.m (30 - 50 in. lbs.)
    • Original Bearings:  2.8 - 5.1 N.m (25 - 45 in. lbs.)
      NOTE:

      If TTTR is too high, back off adjusters evenly on both sides slightly and check TTTR again. If TTTR is too low, tighten adjusters evenly on both sides slightly and check TTTR again.