m35a3 hydro pump

i have a m35a3 with a winch and the hydro pump is not disengageing. The switch in the cab is working but nothing is happening on the pump. any thoughts.

I'm not sure what you mean by "not disengaging", but if you mean mechanically disengaging it doesn't. The air switch operates a valve. The valve could be stuck. Mine was stuck in a position that did not allow the winch to operate. Sounds like yours may be stuck in an opposite position. Check the valve that is the closest to the winch. You should have a chrome shaft coming out the top with flats on the side and a tapped hole in the center. Put the switch in the off position and put a crescent wrench on the flats of the shaft and see if you can give it a little twist. If the shaft doesn't pull down, give it a tap with a hammer. If this doesn't work check with someone who is familiar with hydraulic circuits. Ron

i checked the valve and when i twisted it nothing happened but if i push it down it goes in and out if i pull up but it did not matter if i had the switch on or not. my other question is does the switch inside work all the time and does that mean that the hydo pump is on all the time? thanks for ur info

The switch operates an air valve that in turn operates the hydraulic valve you were working. When the valve is down, there should be no oil flow to the directional hydraulic valve that controls the winch. It is my understanding that if the engine is running the hydraulic pump is running; the valve acts as a bypass circuit.

You would be well served to get all the TM on this truck; they are full of useful information even if you don't do your own wrenching. Ron

Ok that sounds right this is my first a3 and i have only had it a few months. i have had a2's in the past so i am on a slight learning curve. do u know much about the CWIS mine keeps saying there is a LEAK! but there is none. i hear it tring to inflate but the manifold pressure does ot go up any thoughts on that. also do u know where u can get one of the manuals thanks. john