Bobcat 943 hydro issue

[topfli8979]

Picked up a bobcat 943 that sat for a few years not running. Rebuilt injection pump and she purrs now... But I have been fighting a issue with the right side drive hydraulics. After the oil heats up I pretty much lose all forward movement on right side , but do have stronger reverse. Pulled drive motor , and capped off hydro lines to test pressure . Reverse is 3800-4200 psi, forward is 1800-2000 psi max. I have swapped the two top relief valves, but no change. Still have to get bottom 2 out of pump, it's a tight fit. Other than relief valves, what could cause more pressure in one direction?

 

[SSdoxie]

I think you are on the right track looking at relief valve if loss of pressure is only on 1 side in 1 direction.