im working on a cat 508 grapple skidder. the hydraulics for arch lift and grapple function are very slow. grapple rotate is ok. i pressure tested the pump. im getting 2600 PSI at full relief on all functions. it takes about 12-15 seconds to completely lift the arch. steering and blade functions are normal. im thinking either i have a restriction in the supply line or the valve is bypassing. i dont have a service manual for the machine