ROLLER GP-DFLG 4999049 - Caterpillar

Introduction
The problem identified in this technical information bulletin does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below. The troubleshooting process that is defined below should help reduce troubleshooting time and repair costs.Problem
There have been failures reported against the tilt cylinder line relief valves on the 980H Wheel Loaders. The failures are normally described as bucket drift. The relief valves in question are the head end 4T-4932 Relief Valve Gp and the rod end 4T-4933 Relief Valve Gp . The relief valves are of identical design but have different input pressure settings.Solution
Use the following process to troubleshoot for tilt circuit drift:
Isolate the tilt cylinder from the circuit in order to check for cylinder internal leaks.
If the tilt cylinder does not drift when isolated from the circuit, replace the line relief valves with the appropriate current part numbers.
Provide a detailed report of any relief valve failures in SIMSi.