Chevrolet Silverado / GMC Sierra. Service manual — part 2555

8. If rippling or brinelling is present, replace the affected components.

Rippling or brinelling is caused by the following conditions:

A combination of inadequate lubrication, high flank loads, and low peripheral speeds

Friction-induced vibration

Fig. 139: Inspect Gear Teeth For Light Scoring - Rough Partially Porous Lines Or
Areas Aligned In Direction Of Sliding

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

Courtesy of GENERAL MOTORS CORP.

9. Inspect the gear teeth for light scoring - rough partially porous lines or areas aligned in the

direction of sliding.

When the film of lubricant is torn away between the flanks, this permits direct metal-to-
metal contact causing seizure or welding. These welded zones are immediately torn apart
again, producing the damage associated with scoring. Scoring initially occurs in areas
subjected to high hertz frequency stresses and high sliding speeds usually along the tooth
root and tooth tip. Light scoring only covers part of the entire surface of the flank, or is not
strongly developed and has caused only insignificant wear after smoothing.

10. If light scoring is present, replace the affected components.

Light scoring is caused by the following conditions:

Inadequate oil viscosity

Unfavorable gear geometry

Temporary lack of lubricant

Surface roughness

Faulty heat treatment of the gears

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

Fig. 140: Inspect Gear Teeth For Severe Scoring
Courtesy of GENERAL MOTORS CORP.

11. Inspect the gear teeth for severe scoring.

Severe scoring is the same as light scoring except large areas of the tooth flank are affected.
At an advanced stage, the flank may heat up to such an extent that localized discoloring
occurs.

12. If severe scoring is present, replace the affected components.

Severe scoring is caused by the following conditions:

Inadequate oil viscosity

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

Unfavorable gear geometry

Temporary lack of lubricant

Surface roughness

Faulty heat treatment of the gears

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado