Chevrolet Silverado / GMC Sierra. Service manual — part 2628

the direction of sliding, particularly in the tip and root zones. If there is extreme
overheating, the material softens, causing distortion of the gear teeth such as, bent teeth -
thermal deformation.

21. If damage from overheating is present, replace or repair the affected components.

Overheating is caused by the following conditions:

Temporary or complete lack of lubrication - low oil level

Very high peripheral speeds

Insufficient tooth clearance

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (TZ0)

Fig. 126: Inspect Selector Teeth Of Gears For Gear Change Damage
Courtesy of GENERAL MOTORS CORP.

22. Inspect the selector teeth of the gears for gear change damage.

The tooth edges are worn and chipped and, in some cases, affected by plastic deformation as

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (TZ0)

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 (TZ0)

Fig. 127: 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 (TZ0)