Product Support Program For Installing New Transmission Bearings In Certain 789 And 793 Trucks Caterpillar

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 "PS4817" 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

Problem

The 6V2468 Bearing in the transmission of certain 789 and 793 Trucks may fail. This may cause the 9G7465 Gear to wear the 6Y5475 or 9G7463 Thrust Discs in the number three planetary gear train.

Affected Product
Model & Identification Number

789 (9ZC355-618)

793 (3SJ1-15)

NOTE: Transmissions reworked at the factory will be identified with a "C" or "D" stamped on the transmission case near the S/N plate

Parts Needed

1 - 8C6933 Kit-Gasket

8 - 9G7463 Disc-Thrust

2 - 9G9127 Ring-Seal

1 - 9G9557 Ring-Seal

1 - 9G9568 Gasket

4 - 8M5254 Seal-O-Ring

6 - 8M8157 Seal-O-Ring

1 - 9N4146 Ring-Seal

4 - 1T0550 Pin

1 - 6T5133 Gasket

8 - 9U8243 Bearing

2 - 6V4365 Seal-O-Ring

Action Required

1. Remove the transmission and transfer gears. Refer to the Service Manual.

2. Remove the 9G8755 or 8E6617 Planet Carrier of the number three planetary gear train. No additional disassembly should be required unless a 9G7465 Planet Gear wore the carrier.

3. Remove all four 9G7465 Planet Gears from the carrier and inspect all eight 6Y5475 or 9G7463 Thrust Discs for excessive wear caused by contact with the planetary gear.

A. If the planet gear wore into, but not through, a thrust disc, replace both existing 6V2468 Roller Bearings in that gear with two new 9U8243 Roller Bearings. If no signs of excessive wear are visible, assemble the planet gear, shaft, and bearings using new thrust discs if needed.

B. If a planet gear wore through the thrust disc and into the carrier, the remaining portion of the planetary must be disassembled. Thoroughly clean the entire transmission, controls, lines, oil tank, pump, etc. to remove all debris.

4. Carefully inspect the 9G9303 Planet Carrier components Reverse Carrier) to ensure all thrust discs are in place and planet gears are in good condition.

5. Assemble the transmission and transfer gear.

6. Install the transmission and transfer gear.

Service Claim Allowances

Before Failure

NOTE: This is a 15.0-hour job.

After Failure

NOTE: This is a 45.0-hour job.

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.