Got stuck in my own driveway last night... It has been working fine all winter. I was just in that area replacing the starter and the reverse light switch. I put a new rubber hose piece on the two vacuum lines at the transfer case but still no 4wd. No indicator on the dash either.

What else and where do I check?

 

Did you check down on the axle? Pass side is a diaphram w/vac lines and lamp switch.

here is a pic: http://dodgeram.org/tech/repair/4X4/cad_mechanism.jpg

 

I was in your situation about 6 months ago. Got lots of good help from the folks on this board. First thing - make sure the 4wd indicator light is good. Pull the electrical cable off the CAD, jumper the pins together and turn on truck. If 4x4 light on dash comes on, you know light its circuitry are good. Next adivice I got and took, ditch the vacuum actuated CAD. I spent $200 and about 4 hrs and put in a cable actuated CAD from Posi-LOK. Best time and money I ever spent. Now when I need 4x4, I pull the cable, CAD engages, light comes on, toss the transfer case into 4h or 4l and Bob's your uncle I have 4wd and I know it. The vacuum system for the stock CAD looked really fragile with those skinny little capillary tubes underneath a truck that is supposed to be used like a truck not my grandmother's walker. All is very good now.

 

Cable lock would be a ideal upgrade but $$$ is very limited right now. My job cut me back to 3 day a week. Need to fix this first and may be able to add that later.

I did look at the pass side axle and it looks good. I just figured it would be at the transfer case since I was working in that area right before it stopped working.

 

Just looking doesn't get it all the time. Use a vacuum test gauge at all the vacuum lines. You can pick up a cheap vacuum test gauge at the local parts store. Also, since you mentioned not getting out your driveway, it sometimes does take more than a couple feet for everything to line up properly for the CAD to engage all the way. Maybe you just didn't give it enough room.

 

If you have the line of recently make sure a piece of dirty didn't fall in the line and is not blocking it. I had this happen after I did my clutch. If you remove the soft hoses from each end of the hard line you should be able to blow throught them. If that all turn up fine, make sure you have vacuum at the out bound line to the front axle. You will need to have the truck running and in 4x4. After make sure you still have vacuum at the actuator. If it still doesn't work you may need to remove the actuator to make sure it is not bound up.

 

You can pull the axle actuator off and manually move it from side to side to confirm movement, you can also start the engine with it off the axle to confirm it is moving by vacuum. If your on a budget you can slide the axle locking collar over on and find something to hold the CAD in its lock position to get you by till you can replace it. I would recommend the Posi-Loc system as well. I put one on my truck and don't regret it one bit, Its not that much more than the OEM parts and is 100% reliable and you know when its engaged !

 

Had a chance to pull it into the shop I work at and found the vacuum line by the firewall had broken at the tee. Problem fixed. I will kolkata the posi lock as a future upgrade

Thanks for the replies