I have a 140 that surges at low speed. If I hold the hyd. lift lever forward or back the surging stops, and I can drive at low speed also it works fine at full speed. The fluid level is good. Does anyone know what could be causing this problem I'm having?
Tim thanks but I think I should word myself better. The engine is not surging. It's the transmission. I have the engine full throttle and if I try low speeds I get a surging unless I hold the hyd. lift lever back or forward. It also works fine when I'm at a higher rate of speed all the while at full throttle. Engine is steady it's the trans making it surge, also the fluid is good and I installed new check valves about two years ago.
You stated you installed new check valves. Did you also install new Charge Pump & Implement Relief Valves?
Possibly at WOT the system pressure is high and the Charge Pump Relief Valve is cycling open and closed until the system opens and the demand for pressure is diverted to the either the transmission and/or implements.
If your check valves are operating correctly, the pump relief valves are the next place I would check.
Performing an Implement Circuit Pressure Check (500 PSI ± 50 PSI – fully open circuit) along with a Charge Pressure Test (1/2 throttle – 75 – 110 PSI) will help to isolate the problem.
Have you done these checks? If so, are you within spec's?
Richard - You type faster than I do.
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