PLATE AS 6Y4769 - Caterpillar

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 "PS4560" 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
March 31, 2000Problem
The torque limiter needs to be reworked to improve hydraulic performance on certain 416C, 426C, 428C, 436C and 438C Backhoe Loaders. The torque limiter can reduce the hydraulic flow too much when in a multi function application (when compared to the B-series Backhoe Loader). This is caused by a lower torque limiter setting and for potential yielding of the torque limiter control spring on the C-series Backhoe Loaders. This fix will not address lift problems or lack of force problems.
Affected Product
Model & Identification Number
416C (5YN1-3799, 1XR1-683)
426C (7WN1-438, 1ZR1-430)
428C (8RN1-1628, 2CR1-4431)
436C (1RR1-303, 2BR1-211)
438C (9KN1-560, 1JR1-606, 1TR1-783, 2DR1-1051)
Parts Needed
1 - 1381976 Valve Group (only if needed)1 - 1555111 Kit - Torque Limiter (Turbocharged)1 - 1558324 Kit - Torque Limiter (Naturally Aspirated)Action Required
See the attached Rework Procedure.
Service Claim Allowances
This is a 4-hour job. If a new 1381976 Valve needs to be installed, an additional 1 hour may be claimed.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.(1-Rework Procedure)Rework Procedure
There are basically two types of tractors in the COSA area:
I. Machines that require TUV valves due to E.C. requirements.For E.C. countries, after installing the torque limiter spring and stop, if the flows do not meet the flow specification at 2200 RPM, install a new 1381976 TUV valve and retest the unit. Flows should now meet the flow requirement.
II. Machines sold into countries not requiring TUV valves.For non E.C. countries, the procedure as given in PS4310 should be used. This is true whether the vehicle is a center pivot (416C, 426C and 436C) or sideshift (428C and 438C).
The changes described in this program are to address problems with multi function cycle times (speed) and/or excessive engine lug. This change will not correct problems of force (i.e. stick force complaints - inability of the machine to lift above our ratings, etc.).
Make sure machine is parked on level surface, engine shutoff and parking brake applied. Also, make sure all implements are lowered to the ground and system pressure has been relieved from all hydraulic circuits before any work begins to perform this rework.
1. Follow all Safety warnings and procedures outlined in the service manual or given on decals on the machine.2. Provide a method of collecting any oil loss that may occur when doing rework. Tools Required:
- Flow meter, (45 gpm minimum) and variable relief valve.- Accurate tachometer (do not use vehicle tachometer).- 5000 psi pressure gauge.- Differential pressure gauge.- Means of measuring hydraulic oil temperature.- 3 mm Allen wrench.- 5 mm Allen wrench.- and