SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 32 (DRIVE AXLES)OVERHAULDIFFERENTIAL CASESELECTING DRIVE PINION SHIM
1999 GMC Forward Control 5.7 R, Automatic

Selecting Drive Pinion Shim

1999 GMC Forward Control 5.7 R, AutomaticSECTION Selecting Drive Pinion Shim
WARNING: This page is about a different car, the 2003 Chevrolet Corvette and 2002 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
  1. Install the differential assembly onto the Differential Holding Fixture (J 42173). Install 4 M8 x 1.25 bolts. Tighten the bolts to 18 ft. lb. (25 N.m).
  2. Install the Differential Centerline Cylinder (J 42168-1) into the left bearing race bore of the differential housing. Install the Holding Strap (J 42168-9) and thumbscrew to the J 42168-1. Tighten the thumbscrew until snug.
  3. Install the bearing races into the pinion housing/cage. Refer to Drive Pinion Assemble Install the Pinion Housing Centering Spacer (J 42168-1), bearings, spacer, Shim Gauge Assembly (J 42168-2), and bolt to the pinion housing/cage . See Fig 1. Tighten the bolt until sung.
    Fig 1: Assembling Pinion Bearing Assembly
    G00061887Courtesy of GENERAL MOTORS CORP.
  4. Install the pinion housing/cage assembly into the differential housing. The use of M8 x 1.25 dowels or long bolts will ease in pinion housing installation and alignment.
  5. Install the pinion housing/cage bolts. Tighten the bolts to specification. See TORQUE SPECIFICATIONS .
  6. Using a feeler gauge, measure the distance between the J 42168-2 and the J 42168-1. Record the dimension as "B1". See Fig 2.
    Fig 2: Drive Pinion Shim Selection
    G97E03675Courtesy of GENERAL MOTORS CORP.
    7. NOTE: The A1 value is a manufacturing variation between the ring gear and pinion. The A1 value may be higher, lower, or equal to 4.055 in. (103.00 mm) nominal value. When subtracting the A nominal value from the A1 value, the B3 calculation may compute to a positive, negative, or zero total.
  7. Locate the "A1" value on the side of the ring gear. Subtract the A nominal value of 4.055 in. (103.00 mm) from the "A1" value. Record the calculation as "B3".
  8. Add the "B2" value to the "B3" value for the proper pinion housing shim thickness. The "B3" value may be a positive, negative, or zero value. Select shims equal to the calculated value. It may be necessary to round the shim or shims total to obtain the proper size shim pack. If the shim thickness calculation is past the midpoint value, round the number higher to the next decimal value.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.