Air leaking around transfer case shift air valve

[superstuck]

I have an M939 with an air leak. It seems to be leaking from the air valve that is actuated when the transfer case is shifted into low range. Air leaks either from this valve, or VERY near this valve even when the transfer case lever is left in high range and the from axle is engaged using the switch on the dash. I suspect a faulty valve but thought I would confirm that diagnosis here before replacing it. Any suggestions?

 

[73m819]

You do not need that transfer case air switch, all it does is auto engage the front end in low, take it out of the circuit, connect and plug what is needed, then use the dash air switch to engage the front drive, this WILL also take the odds way down of breaking the transfer case in in low reverse.

 

[superstuck]

Perfect I will remove the valve, Could someone show me pics or a diagram or carefully explain how to reconnect the air lines to bypass this valve?

 

[superstuck]

Could anyone who has deleted this valve chime in with where to connect those three air lines?

 

[Csm Davis]

Superstuck you will need to find exactly where your air leak is first, if it is on the body of the transfer case it is not the valve 73m819 spoke of, that valve is next to the adjustable arm in the linkage going to the transfer case right at the back side of the cab. You can move it to where it will not engage with the linkage and or plug the air supply line going to it and or bypass it by running the other two lines together, your choice. The leak and this valve may not be the same thing.

 

[superstuck]

I have removed the valve, it was definitely the problem! It was cracked and I could feel/hear air coming from the fractured area. I have another valve to install but I plan to bypass this system anyway so rather that put the new one in and swap the linkage, I was considering plumbing around it. I know which of the three lines is constant supply, I just done know how to hook things up so only the dash switch engages the front axle.

 

[Andyrv6av8r]

I have removed the valve, it was definitely the problem! It was cracked and I could feel/hear air coming from the fractured area. I have another valve to install but I plan to bypass this system anyway so rather that put the new one in and swap the linkage, I was considering plumbing around it. I know which of the three lines is constant supply, I just done know how to hook things up so only the dash switch engages the front axle.

Plug the one that is constant supply and hook the other 2 together.