SOCKET-1 5/16" 9U6557 - Caterpillar

Problem
Contact of the tooth tip, between the bevel gear and pinion, may result in pitting and spalling of the pinion teeth on certain 789 Trucks. A new differential gear group design provides tip relief for the pinion and bevel gear which increases the service life of the differential and bevel gear group.
Affected Product
Model & Identification Number
789 (9ZC1-489)
Parts Needed
1 - 5P4539 Cone1 - 5P4540 Cup1 - 6V7714 Cone1 - 6V7715 Cup1 - 8X7231 Gear Gp.Action Required
If pieces of the pinion gear teeth are found on the magnetic plug, remove and disassemble the differential group. Rebuild the differential group using a new 8X7231 Gear Group and new pinion bearings.
If the differential group is removed for any other reason, and hard line contact (pitting/spalling) is seen on the pinion gear, install the new 8X7231 Gear Group. If no pitting or spalling is seen, reuse the original gear group.
Service Claim Allowances
This is a 34-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.