My son bought a 98 1500 4x4 with a manual trans. His 4wd was not working and after checking his vacuum lines they were all un hooked and had plugs in them. I found a diagram and hooked them back up. Now when he shifts into 4wd the light comes on but the front axle don;t seem to engage. I don't have a gauge to see how much vacuum the CAD has but by putting the line on my finger it has vacuum when it is switched into 4wd. What should be the next step to check for. Thanks.

 

How are you determining the driveshaft isn't doing its job?

Generally, if the light comes on, that means the fork is all the way over, and the front axle should be engaged.

Does the t-case turn the front shaft?

 

The front shaft does turn. Guess not the best way to tell, but it was getting dark so I had him try to pull up in the yard which isn't very steep and just the back tire would spin.

 

I think this might be a test: Shift into 4 wheel drive drive a few feet (4x4 light should be on) , stop, put on parking brake. Jack up right front wheel and try to hand spin. If it doesn't spin I believe it is in 4 wheel drive, if it turns freely I believe it is not really in 4 wheel drive. Also try to spin front driveshaft, if it does spin I think that might be something in transfer case not right?

 

Pull the CAD off the diff and inspect it/test it, make sure the collar is moving freely over the two axle shafts as well if there is a collar in there. Next would be to pull the front diff cover make sure all the parts in in good working order and that they are there. It was plugged off for a reason now you have the fun of finding out why it was disconnected. For all we know there could be no ring and pinion in the front diff.

 

I did jack the front passenger tire up while in 4wd and it would turn free. Is there a detailed diagram or anything that I could go by for the CAD I have never had any dealings with one. Thanks again for all the help.

 

You can download the Factory service manual here on DF it will walk you through the job at hand and much more.

Page 102 in the 2001 FSM will get you started.

https://dodgeforum.com/forum/2nd-gen...e-manuals.html