Chevrolet Silverado / GMC Sierra. Service manual — part 871

Fig. 108: Identifying Transmission Mount Nuts
Courtesy of GENERAL MOTORS CORP.

3. Lower the transmission.

4. Install the transmission mount to the transmission support retaining nut or nuts.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Tighten: Tighten the nut or nuts to 50 N.m (37 lb ft).

5. Remove the transmission jack.

6. Lower the vehicle.

TRANSMISSION REPLACEMENT

Tools Required

J 21366 Converter Holding Strap

J 44257 Connector Removal Tool

Removal Procedure

1. Remove the transmission fluid level indicator.

2. Remove the starter motor. Refer to Starter Motor Replacement (4.3L) or Starter Motor

Replacement (4.8L, 5.3L, 6.0L, and 6.2L) or Starter Motor Replacement (6.6L) .

IMPORTANT: If replacing a failed transmission, the "FastLearn" (adapt)

procedure must be performed. This can be done in one step using
a scan tool. If this procedure is not done, the transmission
control module's (TCM's) adaptive values will still be at the
settings that it learned for the old transmission, and will be in
slow adaptive mode. Under these conditions, it would take an
unacceptably long time for the adaptive values to converge to
levels suitable for the new transmission.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 109: View Of Torque Convertor Bolt
Courtesy of GENERAL MOTORS CORP.

3. Rotate the engine clockwise, using the crankshaft bolt in order to access the torque

converter bolts through the starter opening. Have an assistant rotate the engine while
aligning the bolts.

4. Remove the torque converter bolts.

5. Completely raise the vehicle.

6. Drain the transmission fluid.

IMPORTANT: Rotate the engine clockwise ONLY, rotating the engine

counterclockwise may loosen the crankshaft balancer bolt.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 110: Range Selector Cable Heat Shield
Courtesy of GENERAL MOTORS CORP.

7. Remove the range selector cable heat shield bolts.

8. Remove the range selector cable heat shield.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - Allison - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado