PUMP GP-PISTON 1377740 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
Reports from the field indicate that the ring in the undercarriage frame assembly has cracked on a very small population of machines. The crack occurred on certain machines in a severe application with a high load factor and with high service meter hours. The crack is typically located on the outer circumference of the ring. Refer to Illustration 1 and Illustration 2.Solution
If the ring in the undercarriage frame assembly is cracked, replace the frame with a new undercarriage frame assembly. If the frame is replaced, a minimum level of parts inventory is being maintained in order to minimize downtime. Dealers should continue to report the cracks in the ring through DSN and SIMS. Include a clear description of the failure in the report. The Product Support Group continues to closely monitor this issue.The part numbers of the affected frames are listed in Table 1. The affected machines are listed in Table 2.
Table 1
Affected Undercarriage Frames    
Part Number    Description    
163-3534     Undercarriage Frame As    
176-2135     Undercarriage Frame As    
236-8341     Undercarriage Frame As    
254-3022     Undercarriage Frame As    
Table 2
Affected Machines    
Model    Serial Number Range    
320C     S/N:GNG1-4387    
S/N:BPR1-6847
320C L     S/N:EAG1-940    
S/N:HKT1-1592
S/N:BRX1-1347
320D     S/N:JFZ1-208    
S/N:JGZ1-2933
320D L     S/N:MDE1-1192    
S/N:MGG1-131
Illustration 1 g01620927
Undercarriage Frame Assembly (1) 4I-3020 Ring
Illustration 2 g01620921
Undercarriage Frame Assembly (A) Typical crack