Chevrolet Silverado / GMC Sierra. Service manual — part 834

not present

The threads in one or more of the converter bolt holes are damaged

Correct the condition with a new thread insert.

Transmission failure did not display evidence of damaged or worn internal parts, steel
particles or clutch plate lining material in the unit and in the control main filter or suction
filter

FLEXPLATE/TORQUE CONVERTER VIBRATION TEST

To determine and correct a torque converter vibration, use the following general procedure to
achieve the best possible torque converter-to-flywheel balance. Refer to Transmission
Replacement for detailed procedure steps as appropriate.

1. Disconnect the battery.

2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .

3. Remove the starter motor bolts and position the starter motor aside. 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) .

CAUTION: Refer to BATTERY DISCONNECT CAUTION .

2008 Chevrolet Silverado 1500

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

Silverado

Fig. 2: View Of Torque Convertor Bolt
Courtesy of GENERAL MOTORS CORP.

4. Remove the torque converter bolts.

2008 Chevrolet Silverado 1500

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

Silverado

Fig. 3: Accessing Torque Converter Bolts
Courtesy of GENERAL MOTORS CORP.

5. Rotate the torque converter one bolt position.

6. Install the torque converter bolts.

Tighten: Tighten the bolts to 60 N.m (44 lb ft).

7. Install the starter motor and starter motor bolts. 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) .

NOTE:

Refer to Fastener Notice .

2008 Chevrolet Silverado 1500

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

Silverado

8. Connect the battery.

9. Start the vehicle and test for vibration again. If vibration is still present, repeat the testing

procedure. Repeat this procedure until you obtain the best possible balance.

NOISE AND VIBRATION ANALYSIS

A noise or vibration that is noticeable when the vehicle is in motion MAY NOT be the result of
the transmission.

If noise or vibration is noticeable in PARK and NEUTRAL with the engine at idle, but is less
noticeable as RPM increases, the condition may be caused by unsatisfactory engine performance.

Inspect the tires for the following conditions:

Uneven wear

Refer to Tire Diagnosis - Irregular or Premature Wear .

Imbalance

Mixed sizes

Mixed radial and bias ply

Inspect the suspension components for the following conditions:

Alignment and wear

Loose fasteners

Refer to Fastener Tightening Specifications .

Inspect the engine and transmission mounts for damage and loose bolts.

Inspect the transmission case mounting holes for the following conditions:

Missing bolts, nuts, and studs

Stripped threads

Cracks

Inspect the flywheel for the following conditions:

Missing or loose bolts

Cracks

CAUTION: Refer to BATTERY DISCONNECT CAUTION .

2008 Chevrolet Silverado 1500

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

Silverado