SPACER 1682100 - Caterpillar

Caterpillar: Confidential Yellow
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.
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 "PS4592" as Part Number, "7755" as Group Number, and "96" as Description Code.
This Revised Service Letter replaces the May 12, 1991 (Revised February 1992) Service Letter. Changes have been made to the Affected Product and Service Claim Allowances.
Termination Date
December 31, 1992Problem
An excessive amount of end thrust from the PTO drive line may cause wear on the 7C4812 Adapter and 7C6524 Gear Assembly in the rear power take-off of certain 3306B Truck Engines.
Affected Product
Model & Identification Number
3306B (63Z4000-21496)
Parts Needed
1 - 7C4818 Gasket-Flywheel Housing1 - 7C6524 Gear Assembly4 - 3F6795 Dowel1 - 5F3106 Seal1 - 7H7107 Seal1 - 9H5921 Gasket1 - 5L5032 Seal1 - 4P4178 Plate1 - 4P4181 Plate1 - 5S8543 Bearing1 - 4W0452 Seal-CrankshaftAction Required
See the attached procedure.
Service Claim Allowances
*Caterpillar will pay 100% of the labor allowed per the Time Requirement Guide as shown in the labor breakdown. Any additional operations must be justified and explained in the claim story.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach. (Rework Procedure)Rework Procedure
Remove the transmission and flywheel housing.
Remove the 7C4812 Adapter from the flywheel housing.
Remove the 5S8543 Bearing from the 7C4812 Adapter.
Machine the 7C4812 Adapter to the dimensions shown in Illustration 1. If the cast drain slot is completely machined away after the 7C4812 Adapter is machined, use a small mill cutter to cut a drain slot in the same location as the original cast groove. Failure to provide a drain will allow oil pressure to build up behind the gear which will overload the joint.
Install 2-3F6795 Dowels to an assembled height of 3.5 mm (.14"). Install the 4P4178 Thrust Plate on the adapter. A soft hammer maybe required to seat the thrust plate on the dowels.
The thrust plate fits tight on one dowel and floats on the other dowel.
Install the new 5S8543 Bearing in the 7C4812 Adapter. Make sure the bearing is installed until it is flush with the surface that was not machined. See Illustration 1.
Machine the 7C4820 Flywheel Housing to the dimensions shown in Illustration 2.
Install 2-3F6795 Dowels to an assembled height of 3.5 mm (.14"). Install the 4P4181 Thrust Plate on the adapter. A soft hammer maybe required to seat the thrust plate on the dowels.
The thrust plate fits tight on one dowel and floats on the other dowel.
Do not reuse the existing 7C6524 Gear Assembly. Use a new 7C6524 Gear Assembly or damage to the power take-off may result. The axial end play tolerance is .15-89 mm (.006"-.035")
Illustration 1
Illustration 2