Chevrolet Silverado / GMC Sierra. Service manual — part 2558

a result of high shift loads - ragged edges. Such severe deformation of the selector teeth
edges will cause hard gear shift changes. The spline flanks may also show signs of wear
resembling fretting corrosion.

23. If gear change damage is present, replace or repair the affected components.

Gear change damage is caused by the following conditions:

Corresponding speeds of gears not adequately matched

Operating the transmission incorrectly

Incorrect clutch operation

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (M96) - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Fig. 147: Inspect Gears For Corrosion
Courtesy of GENERAL MOTORS CORP.

24. Inspect the gears for corrosion.

Corrosion may appear as brownish red to black spots, sometimes with local material loss on
the flank. If corrosion has not caused material loss to the flank, the sliding and rolling action

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (M96) - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

of the flank can help to remove some of the corrosion.

25. If corrosion is severe, replace the affected components.

Corrosion is caused by the following conditions:

Water or slat water entering the transmission

Condensation forming under unfavorable operating conditions

Oil aging and the decomposition of corrosion inhibitors

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (M96) - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Fig. 148: Inspect Reverse Idler Gear For Brinelling
Courtesy of GENERAL MOTORS CORP.

26. Inspect the reverse idler gear for brinelling.

This type of damage occurs on the roller races of the idler gear. This type of damage is
characterized by what appears to be the impression of the bearing rollers. If the bearing only

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (M96) - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado