So, I helped my friend get his truck (F250) out of the mud with my truck. It was the first time I really used my 4x4. So i put it in park, then put it in 4h, but I didnt see the '4x4' light come on on the dash. I got my friend out without any problems, but I really dont even know if it was in 4x4 or not. Does any one else have a problem with there light not coming on?

 

Underneath the front of the truck, right under the bumper is a plug. I can't really describe what it looks like with out going out and looking at it myself, but it likes to come unplugged, and is usually left unhooked from a front end collision repair job.

Are you 100% in saying that the truck locked into 4wd?

 

Im really not all that sure. It didn't really feel any different. But I think it was.

 

Well, the reason I say that is because it's very common for the CAD to stick and then the system wont engage.

Another common issue is the two vacuum lines right in front of the transmission (red and black plastic lines with rubber boots on the end) that love to fall off and with out the system getting the right pressures, the 4wd will not engage there either.

Really, you just gotta do some investigation at this point.

 

Okay, thanks man.

 

Yea, those lines leading into the CAD are also brittle after time and mine somehow got melted (i noticed only after getting stuck in the mud).

 

i had the same problem with my truck, the PO even took off a good chunk of the value cause it didnt work.
i ended up replacing a $10 4x4 selector switch from napa (its a vacuum actuated switch on top of your t-case.), and everything works like it should.

 

here you go.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm