Chevrolet Silverado / GMC Sierra. Service manual — part 1128

Fig. 385: Checking Sun Gear Rotation
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: If the forward clutch sprag assembly operates backward, you

have installed the sprag backward. Reassemble the sprag

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

11. Test the forward clutch sprag assembly for proper operation.

1. Position the forward clutch sprag assembly with the input sun gear facing up.

2. Hold the forward sprag clutch outer race (644) with one hand and rotate the input sun

gear (640) with the other hand.

12. Install the forward clutch sprag and input sun gear assembly into the input clutch housing.

13. Index the overrun clutch hub into the overrun clutch plates.

FORWARD CLUTCH ASSEMBLY ASSEMBLE

correctly.

IMPORTANT: The sun gear should only rotate in a counterclockwise

direction.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Fig. 386: Inspecting Forward Clutch Assembly For Wear Or Damage
Courtesy of GENERAL MOTORS CORP.

1. Inspect the forward clutch waved plate (648), the apply plate (646), the fiber plate

assemblies (649B), the steel plates (649A) and the selective backing plate (650) for the
following conditions:

Damaged tangs

Delamination

Excessive wear

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Heat damage

Flatness

Surface finish damage

Burrs and nicks

Fig. 387: Identifying Forward Clutch Apply Plates
Courtesy of GENERAL MOTORS CORP.

2. Install the forward clutch apply plate (646).

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado