TRACK GP 5354844 - Caterpillar

TECHNICAL INFORMATION BULLETIN May 12, 2004
Track-Type Tractors D8RII (6YZ, AKA)
Component Code(s) 3066SUBJECT: TRANSMISSION PUMP DRAIN PASSAGE MISSING
PROBLEM:
Transmission pumps have been found in the field that have a defect in the front housing that causes the gear in the rear pump section to wear heavily into the rear cover. The 160-1835 Transmission Pump uses a 161-9939 Body Assembly. The drain passage for the idle gear shaft was not drilled deep enough in some housings. The absence of a drain passage behind the shaft allows pressure to build on the end of the shaft. The force on the end of the shaft pushes the shaft and the gear in the rear pump section into the cover on the end of the pump. This will cause the pump to create excessive clearances between the gear and the sealing surface. The rear pump section will loose the ability to develop pressure. The rear cover on the pump will have an appearance similar to the housing shown in Illustration 1.
Illustration 1 - Housing machined by pump gear
SOLUTION:
Inspect the housing in the front section to determine whether or not the drain passage has been properly machined. The drilled drain passage must intersect with the bearing bore for the idle gear shaft. If the end of the bearing bore does not intersect the angle-drilled passage, then replace the 161-9939 Body As.
Illustration 2 ? Housing Drain Passage
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