2001/09/01 Caterpillar

Truck Engines:

3126 (S/N: 1WM1-UP)

3126B (S/N: 7AS1-UP)

Some of these engines have air compressors that have been modified for use with a hydraulic pump. These engines may be equipped with an air compressor group that has splined shafts that have 11 teeth or these engines are equipped with an air compressor group that has splined shafts that have 13 teeth. The type of air compressor can vary depending on the OEM and the specific application. These engines may be equipped with any of the following air compressors groups:

• 123-6356 Air Compressor Group

• 144-0746 Air Compressor Group

• 150-7638 Air Compressor Group

The 123-6356 Air Compressor Group has been cancelled and replaced by the 144-0746 Air Compressor Group. Both of these air compressor groups have splined shafts that have 11 teeth. Some of these air compressors groups may have splined shafts that have been modified from 11 teeth to 13 teeth by the OEM.

The 150-7638 Air Compressor Group has splined shafts that have 13 teeth. The 150-7638 Air Compressor Group can be used as a direct replacement for a 123-6356 Air Compressor Group or a 144-0746 Air Compressor Group that has been modified to splined shafts that have 13 teeth.