Usage:
NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4712" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
August 31, 1993Problem
Spalling may appear on the planet shafts in the final drives of certain 776 and 776B Tractors; and 777 and 777B Trucks. A new bearing with inner race may be installed. A new planet gear is required with the new bearing.
Affected Product
Model & Identification Number
776 (14H1-371)
776B (6JC1-97)
777 (84A1-75046, 84A75101, 84A75102)
777B (4YC1-1671; 3NF1-42)
Parts Needed
- 2 - 3D3295 O-ring Seal
- 2 - 4D0449 O-ring Seal
- 12 - 8E7945 Bearing
- 6 - 8X7164 Shaft
- 18 - 8X7931 Spacer
- 6 - 8X9157 Gear
- 2 - 4D0449 O-ring Seal
Action Required
Remove the existing planet bearings, spacers, and gears from the final drives, thoroughly clean the final drive compartment, and install the new parts. If the shafts have no surface damage, they can be used again. Installation of the new bearing requires the shafts to be installed with a 30 ton press or frozen. See illustration for parts affected.
NOTE: Worn or loose wheel bearings can effect final drive planet shaft, bearing, and gear live. Wheel bearing bre-load adjustment should be checked. Any worn or damaged parts associated with the wheel bearings should be replaced or salvaged. Refer to the October l9, 1991 Service Letter - PS4711, service magazine article dated July 8, 1991 "Procedure To Prevent Rear Wheel Bearing Cones From Rotating On Axle Housing", and Guideline For Reusable Parts form number SEBF8083 "Procedure To Repair Worn Wheel Spindles And Hubs On Off Highway Trucks.
The cost of wheel bearing repair and or spindle salvage is not included in this program.
Location Of Parts Being Installed
Service Claim Allowances
NOTE: This is a 6-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.