Hummer H3. Manual - part 1505

Fig. 154: Identifying Slight Pitting On Gear Teeth
Courtesy of GENERAL MOTORS CORP.

23. Inspect the gear teeth for slight pittings.

Slight pittings are identified as pore-like areas of individual pittings on the flank caused by
material fatigue. Usually, slight pittings are only present in the root zone of the flank. Slight
pittings may cease after run-in. A change in operating conditions may also stop continued
development of slight pitting.

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

Fig. 155: Identifying Pitted Gear Teeth
Courtesy of GENERAL MOTORS CORP.

24. Inspect the gear teeth for pittings.

Pittings are material fatigue on the flank. The total pitting surface may become so large that
smooth running is considerably impaired or the remaining flank face still bearing the load
will soon be destroyed by wear.

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

25. If pittings are present, replace the affected parts.

Pitting is caused by the following conditions:

Exceeding the sliding and rolling stresses for the material

Incorrect oil viscosity

Excessive operating temperature

Fig. 156: Identifying Spalling On Gears
Courtesy of GENERAL MOTORS CORP.

26. Inspect the gears for spalling.

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

Spalling is extensive triangular pits on the flank, spreading from a zone of gray spots or a
fine line of pits at the root. The depth of the exposed surface is relatively constant
throughout. Further cracks may extend from the pits at an angle. In some cases, the damage
may even progress into the tip zone, causing tip damage.

27. If spalling is present, replace the affected parts.

Spalling is caused by the following conditions:

Exceeding the sliding and rolling stresses for the material

Incorrect oil viscosity

Excessive operating temperature

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

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