Have a Toyota 7FGU25. The hydraulic pump has exploded for the 3rd time now. The first time I replaced the pump I found the air governor was not working correctly. Replaced the governor and put it back in service. I thought the engine RPM being to high caused the pump failure. The second pump failure I checked the pressures. Set the relief to 1900lbs which is below spec. Now I have 3rd pump failure. At a loss as to what to look for. Hoping you guys can point me in a direction. This truck is operated in a super dusty and rough environment. All three pump failures are identical. The rear of the pump where the high pressure hose comes out and goes to the control valve, splits. Please help.