When I am in 4wd HI and I hit the 30 to 40 mph range the 4wd cuts out. The light turns off and I can hear the axles in the front disengage and then re engage when i slow down to about 30 and then the light comes back on again. It does it randomly not all the time. Idk if these trucks are designed that way to shut off at a certain speed or not. I also replaced the CAD last winter so I dont think its that. Anybody know what this could be?

 

Check valve in the vacuum lines is bad. I bet your vents switch too?

 

How can I get to the check valve? And what do you mean by the vents switch?

 

Your heater vents. Do they move to defrost at about the same time?

Check valve should be located on the passenger side, right next to the intake manifold, before the lines split off to go to the t-case, and the inside. Little round feller, 'bout an inch in diameter (if that.) We had another member with a 96 that didn't have one at all.

You also need to check for vacuum leaks on the lines to the t-case, and up to the axle.

 

http://www.dodgeram.org/tech/repair/..._engagment.htm

https://dodgeforum.com/forum/2nd-gen...ild-vents.html

 

Okay guys thanks for the info. When I get a chance I will take a look at the lines and stuff. Thanks again.