Drive right side not responsive

[L445]

Hello, Ive a NHL445, right side drive both forward and reverse lacks in response to stick position. Still moves but handle travel to get right side to respond is excessive and full speed travel in not there. All filters changed, mesh screen clean. collar gear and mechanical connections to hydraulic pump all tight. IVe read it could be the pressure relief valve on the main hydraulic pump for the right side and Ive also read it could be the hydraulic pump itself. Parts replacement gets expensive quickly. Any incite to isolate and test would be helpful. Left side drive works just fine. thnaks

 

[Mike10]

Take the seat out and watch the linkage as you move the control lever. Check for excess movement of the linkage without the levers attached to the hydro pumps moving. Also check the bolts which clamp the levers to the hydro pump shafts so they are tight.