KIT-GASKET 6V1681 - Caterpillar

Caterpillar: Confidential Yellow
PSP FOR FUEL TRANSFER PUMP VALVES; 3406B TRUCK,MARINE, INDUSTRIAL, GEN SET ENGINES; 16G MOTOR GRADERS; 245 EXCAVATORS & F RONT SHOVELS; 824C TRACTORS, 825C, 826C COMPACTORS; 980C LOADERS - PS4021 - MAILED US, CANADA, CFEL AND COSA
  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.
PRODUCT SUPPORT PROGRAM FOR FUEL TRANSFER PUMP VALVES; 3406B TRUCK, MARINE, INDUSTRIAL, GENERATOR SET ENGINES; 16G MOTOR GRADERS; 245 EXCAVATORS AND FRONT SHOVELS; 824C TRACTORS, 825C, 826C COMPACTORS; 980C LOADERS, 1256, PS4021 U-81 C-65 E-55 O-52 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 "PS4021" as Part Number and "7755" as Group Number. Although products in the field are to be administered as described above, dealers should purge parts stock immediately. A Service Letter similar to this one has been sent to all TEPS Dealers. Termination Date
October 31, 1986.
Problem
The fuel transfer pump on the above engines has three 1W6182 or 7W402 Valve Assemblies. The one valve in the piston can break in extremely cold weather. Some damage can also occur to the other valve assemblies. This problem has been reported mainly in cold weather applications. A new valve with improved cold temperature capability is now used in the piston and at the other two locations in the pump. These valves are directly adaptable to earlier engines.
Affected Product
Some of the following vehicles contain the 3406 Engine with the former scroll fuel system and are not in this Program. Model Identification/Serial Number 3406B Truck Engine 7FB1-41754 3406B Marine Engine 4TB1-641 3406B Industrial Engine 6TB1-2539 3406B Generator Set 2WB1-2692 16G Motor Grader 93U2284-2523 245 Excavator 95V1084-1193 94L525-751 245 Front Shovel 82X618-633 84X686-857 621B Tractor 2GB124 45P3521-3827 623B Tractor 46P1957, 1971-2198 627B Tractor 14S1188, 1191, 1212, 1220, 1237, 1252, 1253, 1267, 1277 15S1729 824C Tractor 85X958-1174 825C Compactor 86X634-730 826C Compactor 87X338-559 980C Loader 63X4923-6349