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Chevrolet Silverado / GMC Sierra. Manual - part 2625
5. Inspect the gear teeth for abrasive wear.
The marks left by the machining process are erased from the active flank. Instead, the entire
flank takes on a matte gray appearance. Substantial changes take place in the tooth profile
and clearance once abrasive wear has reached an advanced stage. This not only increases the
noise level, but can cause secondary damage.
6. If abrasive wear is present, replace the affected components.
Abrasive wear is caused by the following conditions:
Oil contamination resulting from wear or surface fatigue in other areas of the
transmission
Sand, sludge, etc. penetrating into the transmission from the outside
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (TZ0)
Fig. 118: Inspect Gear Teeth For Rippling Or Brinelling
Courtesy of GENERAL MOTORS CORP.
7. Inspect the gear teeth for rippling or brinelling.
The polished tooth flanks show signs of ripple-like alterations in the surface structure which
run perpendicular to the direction of sliding, resembling a washboard.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Manual Transmission - Tremec 5-Speed (TZ0)
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. 119: 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 (TZ0)
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 (TZ0)
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