2000 3/4 ton, 5.9 gas, 4x4 automatic trans. The problem is when I shift the lever into 4x4 hi or low the trans. won't go into 4 wheel drive. The 4x4 indicator light does not light up either. I checked the linkage and it is shifting or atleast it's moving nothings froze up. Truck runs just fine in 2 wheel drive with the 4x4 shift lever in any position. Wondering if there is a sensor that I have to replace. Any info would be appreciated.
THANKS etnraw

 

is there vacuum to the CAD?

 

welcome to df.

shifting of the t-case is all mechanical.
look for the rotation (or lockup) of the front drive shaft as an indicator that t-case is engaged and sending power to the front diff.
this step rarely fails.


after that, the 2 piece axle lockup, and 4wd indicator is vacuum controlled, which is prone to all kinds of malfunction.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm

 

Thanks for the input I will check the CAD and go from there.

 

my truck did that last year but only into 4wd low it would just pop into neutral all I did was play with the linkage such as loosening the small bolt on the linkage shaft and moving the linkage shaft up and tighten and then tested it it was still doing it so I then loosened it and moved it down and tightened it and it works great im not saying your gonna have to move yours down and it'll be fine but if you do what I did it may work out for you.

Good luck to you, hope you get it all solved before snow hits ya!!!