Chevrolet Silverado / GMC Sierra. Service manual — part 764

TRANSMISSION MOUNT REPLACEMENT (4WD)

Fig. 75: View Of Transmission Mount, Crossmember Nut & Bolts (4WD)
Courtesy of GENERAL MOTORS CORP.

Tighten: 50 N.m (37 lb ft)

2

Transmission Mount Bolt (Qty: 2)

Tighten: 50 N.m (37 lb ft)

3

Transmission Mount
Tip: Raise the transmission with the transmission jack just enough to remove the
transmission mount.

Callout

Component Name

Preliminary Procedures

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

CASE EXTENSION AND GASKET REPLACEMENT

Fig. 76: Case Extension Housing and Seal Replacement
Courtesy of GENERAL MOTORS CORP.

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

2. Support the transmission with a transmission jack.

1

Transmission Mount to Crossmember Nut (Qty: 2)

Tighten: 50 N.m (37 lb ft)

NOTE:

Refer to Fastener Notice .

2

Transmission Mount Bolt (Qty: 2)

Tighten: 50 N.m (37 lb ft)

3

Transmission Mount
Tip: Raise the transmission with the transmission jack just enough to remove the
transmission mount.

Callout

Component Name

IMPORTANT:

The extension housing and drive shaft flange (yolk) on this vehicle are serviced as a complete
assembly. The drive shaft flange seal is a dust shield used to protect the sealed drive shaft flange
bearing that is pressed into the extension housing. The drive shaft flange is pressed into the drive

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

TRANSMISSION OUTPUT SHAFT SEAL REPLACEMENT

Preliminary Procedures

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

2. Remove the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or

Two-Piece Propeller Shaft Replacement .

3. Support the transmission with a suitable jack.

4. Remove the transmission mount assembly. Refer to Transmission Mount

Replacement (2WD) or Transmission Mount Replacement (4WD) .

shaft flange bearing, and is not serviceable. The extension housing should NOT contain any
transmission fluid. If transmission fluid is present in the extension housing, replacement of the
output shaft seal is necessary. Refer to Transmission Output Shaft Seal Replacement.

1

Case Extension Housing Bolt (Qty: 6)

Tighten: 50 N.m (37 lb ft)

NOTE:

Refer to Fastener Notice .

2

Case Extension Housing Assembly
Tip:

Serviced as a complete assembly as shown.

There is no gasket or seal between the extension housing and transmission
case.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 77: Transmission Output Shaft Seal Replacement
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

Preliminary Procedures

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

2. Remove the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or

Two-Piece Propeller Shaft Replacement .

3. Support the transmission with a suitable jack.

4. Remove the transmission mount assembly. Refer to Transmission Mount

Replacement (2WD) or Transmission Mount Replacement (4WD) .

5. Remove the transmission extension housing assembly. Refer to Case Extension and

Gasket Replacement.

1

Output Shaft Seal
Tip:

Use the J 45000 Seal Remover, to remove the seal. See Special Tools.
Use care in order to avoid damaging the output shaft bushing.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado