after about 20 min. of driving ,plow not attached,i opened the hood to add some washer fluid, leaned my hand on the valve body and nearly burnt my hand! the pump was also warmer than i thought it should have been for shuch a short trip but not nearly as hot has the valve body. when the plow is attached and the truck is cold the system works perfectly but after about 15 min. of driving not plowing the plow begins to creep down and will not raise until the engine is raced up considerably.(see my previous post entitled "fisher drops & drive shaft wobbles")is there somthing in the valve body that could be clogged or sticking i can check ? i did change the fluid,the old stuff smelled like low tide at the clam flats 1991 f350, under hood belt driven pump,9'fisher.