I have a massy 360 all wheel drive that makes a whinning noise at the hydralic filter. its for sure not the alternator or the water pump because i took the belt off and it made no difference. I changed the hyd oil filter and it changed nothing. it appears to be at the valve just before the hyd oil filter. has anyone had this problem before? what does this valve do? i can see no reason to have it at all and its not availbe to buy new nor is a kit made for it. any help would be appreciated.