4 wheel drive won't engage
 

I put my truck into 4 wheel drive, I can feel the hubs lock but 4 wheel drive is not engageing. any ideas on how to fix?

Moving this to the correct section.

Does your 4x4 lite come on?

see the link below. 3 things have to happen, in this order.
1 t-case must mechanically shift into 4wd and turn the front drive shaft.
2 you must have engine vacuum on the 2 hoses of the cad, at the right time.
3 the cad must move the collar, and couple the 2 piece passenger side axle.

the easiest way to troubleshoot is to put it up on 4 jack stands and operate it.

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

There is a good chance the cad unit is the culprit

^ usually is. it's a POS.