M931a2 T-case

[greenmonster]

Just got my new M931a2 and I took it out for the first off road run. The front diff is locking in but there is no indicator light, I tried to put it in low range but to my disappointment it did not go in. The lever would not move up. There is a couple of wires going to the button on the end. Is there a low range lock out? I put the trans in neutral and tried putting it in, I also tried to shutting the engine off. Any help would be great.

Thanks

 

[Derrickl112]

They can be a PETA to shift.

 

[greenmonster]

Pain as in I need to pull really hard or pain as in I need to stand on my head push some button and things like that?

 

[wsucougarx]

Be sure your transfer case lever button is unlocking the transfer case lockout. Get your air pressure up. Shut motor off, open your driver side door. Next depress the button on the transfer casr lever. You should hear a click.

 

[greenmonster]

So there is a lock out, Thanks wsu, I hear no click and if I try it before I get air pressure up it moves like butter. When are pressure comes up I can't get it to budge so that makes sense. Now all I have got to do is find out why.

 

[m16ty]

If you trace the wires from the button you will trace them to a air solenoid. The line from the solenoid will go to a air cylinder mounted on the t-case.

On every M939 truck I get my hands on, I disconnect the air line from said cylinder and plug the line and where it goes into the cylinder. Every truck I've done this to shifts much better from high and low. I can't think of anything it hurts doing this mod.

 

[greenmonster]

Will do, I will take some pics of it when I am doing it for future reference..Thanks for all the help

 

[flibob]

I have that tcase problem also thanks for the info. Looking forward to the pics

 

[M35A2-AZ]

Looks like one of my trucks has this problem also.

 

[greenmonster]

Here is the culprit on the t-case and just c case in point it locks it from shifting either way low to high or high to low. There was nothing open today to bypass it but here is a pic of the valve.

 

[m16ty]

Here is the culprit on the t-case and just c case in point it locks it from shifting either way low to high or high to low. There was nothing open today to bypass it but here is a pic of the valve.

Isn't that a pic of the speedometer drive? I know it's not the lock cylinder or solenoid valve.

The valve and cylinder are located on the top toward the front of the t-case.

 

[Doomsday]

I just found out I have this problem as well. Got my "new" M923 all washed up today and went to shift into low to try it out and the lever wouldn't budge. I found a wire that looked shredded all to ****, so gonna try and fix that but a interested to find out more about this "lockout." So, should I just forget about fixing the wire and disconnect the air line and it should shift much easier as described by m16ty?? Please help.

Thanks guys!