I have a Raymond 425-c40tt that has no back tilt once the hydraulic fluid heats up. All other hydraulic functions work fine. It's already had the tilt, priority bypass, and Aux select valves and solenoids swapped with known working parts, as well as CB1 and 2 swapped. There is no leakage past the seals or packing in the cylinders. Any insight would be massively appreciated. Thanks in advance