M35A3 winch control valve question

[Sgt Jiggins]

Hi All,

While in the disengaged (downward) position, the winch control valve on my M35A3 dumps air. If I put it in the engaged (upward) position it stops. Obviously that's not safe, so I removed the valve, disassembled, replaced what could've been a busted oring, and put it back together. Same result. Ok, order a new switch. Same result. I guess it's possible I have 2 bad switches, but......

What am I doing wrong? Air leaks out of the 2 holes on either side of where my thumb is pointing in the picture when the valve is set to 'disengaged'.

Thanks,
SJ/JD

 

[Monkeyboyarmy]

I would guess that the supply line is feeding air back to the switch. I'm not sure what that switch does but possibly a bad diaphragm in the end component.

 

[Sgt Jiggins]

The switch is to enable/disable the "in/out" winch control just a bit further up the shift tower. I'm going to try flipping the switch around tomorrow.

 

[glcaines]

The switch is to enable/disable the "in/out" winch control just a bit further up the shift tower. I'm going to try flipping the switch around tomorrow.

When you say you are going to try flipping the switch around, do you think someone plumbed it backwards and you are going to switch the air lines? Is the winch actually enabled when you flip the switch the way it is connected now? I can't get to my A3 right now, but when I can I'll look and see which way mine is plumbed. You are correct in that the chances of two bad switches isn't high, but who knows?

 

[Sgt Jiggins]

I'd thought of changing where the connectors are attached. But after looking at diagrams, its configured properly. I don't understand how the air supply line would be the problem. And the next device in the line after it is the winch in/out control. Which does work.

The winch is working as it should. But the wcv isn't, leading to the winch in/out being always "live". If I try to put the wcv into "disable", the switch just dumps air.

 

[glcaines]

I'd thought of changing where the connectors are attached. But after looking at diagrams, its configured properly. I don't understand how the air supply line would be the problem. And the next device in the line after it is the winch in/out control. Which does work.

The winch is working as it should. But the wcv isn't, leading to the winch in/out being always "live". If I try to put the wcv into "disable", the switch just dumps air.

I think the switch is designed to dump air from the line once the switch is placed in the off position. Otherwise, when you turn the switch off, the line to the winch will still hold pressure and although the switch is off, the winch is still energized. When I switch the winch to the off position, I hear air dumping from the switch for a short period and then the sound ceases and the winch is inoperative. I'm assuming that yours keeps on dumping air from the switch continuously after switching off?

 

[Sgt Jiggins]

I think the switch is designed to dump air from the line once the switch is placed in the off position.

Oh! That makes sense! I heard it 'dumping' then and just assumed something was wrong. How long does it dump? 3-5 seconds?

 

[glcaines]

Yes, about 3 - 5 seconds.

 

[Sgt Jiggins]

Ok, after further troubleshooting, that valve is not right. If I put it to "disengage" it just dumps air forever. Its surprising (to me) how fast that thing can drain the system down.

So I'm operating with it engaged. Which really bugs me.

It seems to be a fairly simple setup. WTH am I missing?!

 

[glcaines]

Ok, after further troubleshooting, that valve is not right. If I put it to "disengage" it just dumps air forever. Its surprising (to me) how fast that thing can drain the system down.
So I'm operating with it engaged. Which really bugs me.
It seems to be a fairly simple setup. WTH am I missing?!

This has me confused as well. As you say, this is a very simple setup. Are you absolutely certain that the airlines aren't switched? That is the only thing I can think of. If the lines are switched, air pressure will go backwards through the switch and energize the winch with the switch in the up position. When the switch is placed in the lower or off position, the air pressure will exit out the switch continuously, draining the system pressure. I'm almost positive the two lines are reversed as this could explain what is happening. Try switching the two lines at the switch. Leaving it the way it is could be dangerous and might cause damage if someone accidentally hit the other toggle.

 

[Sgt Jiggins]

I looked at it quite a bit and thought the same... maybe they're reversed on the winch control valve itself? Thing is, and maybe I'm doing it wrong(!), but getting them swapped would make it very difficult if not impossible to fit in the tower housing. Can you please take a photo of how yours is installed in your tower? No huge hurry, maybe just next time you're out spending some quality time with your truck.

Thanks!

 

[glcaines]

I'll try to take some photos for you. One question - was your truck originally a winch truck? If not, perhaps whoever installed the winch screwed up and reversed the lines.

 

[glcaines]

I took three photos of the switches and one of the pneumatic lines going to them. It was very hard to see everything at once. I also went underneath the truck, but the location where the lines go through is not visible due to the transmission. After looking at the switches, I really think someone reversed the two lines on the switch. There is one other possibility and that is someone switched the lines under the truck. There are three lines going to the winch. One comes from the main energizing switch - lets call it Line 1. The other two come from the toggle that determines direction of the winch. Another line feeds air pressure to the main energizing switch - lets call it Line 2. If Lines 1 and 2 are switched, this could also cause your issue. I'm not certain where Line 2 is fed from. However, Line 1 is clearly visible and easily accessible from under the winch and should be easy to disconnect. I would recommend finding where Line 1 is fed from. If the line lengths are similar, it should be easy to switch the lines around and see if this fixes your problem. I took a photo of where Line 1 attaches to the winch and it is labeled Winch 4.

 

[Sgt Jiggins]

Pretty sure it was a w/w from the factory. The bill of sale from GL way back when indicated as much.

I could have the 2 bottom lines swapped? I don't know for absolute certain because the guy who took the tranny out died a couple years ago. The guy who just put the rebuilt tranny back in about a month ago had to guess too.

What you showed me is what mine looks like. In/out is correct. The valve... I can try swapping the 2 on the bottom again...

 

[Sgt Jiggins]

I like your rubber matting BTW. Where'd you get it?

 

[glcaines]

I like your rubber matting BTW. Where'd you get it?

All M35A3s came with the matting from AM General. Mine is original.

 

[glcaines]

Pretty sure it was a w/w from the factory. The bill of sale from GL way back when indicated as much.

I could have the 2 bottom lines swapped? I don't know for absolute certain because the guy who took the tranny out died a couple years ago. The guy who just put the rebuilt tranny back in about a month ago had to guess too.

What you showed me is what mine looks like. In/out is correct. The valve... I can try swapping the 2 on the bottom again...

The lines you would need to switch are what I called Line 1 that feeds pressure to the winch from the main energizing switch. The other line that needs to be switch is the line that feeds pressure to the main energizing switch, which is the bottom line going to the switch. I have no idea where this line is fed from. You may need to get someone to move the line up and down through the rubber grommet while you look under the truck to see which line is moving and follow it to where it connects.

 

[Sgt Jiggins]

All M35A3s came with the matting from AM General. Mine is original.

Either mine are missing or I have yet to locate it in the mountain of parts that came with it. I saw where Wes had used 3/4" mats from TSC. Need to get "something".

 

[glcaines]

Either mine are missing or I have yet to locate it in the mountain of parts that came with it. I saw where Wes had used 3/4" mats from TSC. Need to get "something".

I haven't looked recently, but I've seen NOS mats for A3s for sale on Ebay in the past for minimal money.

 

[glcaines]

Have you figured out your hydraulic winch problem?