Recently purchased a 2002 2500 6spd 24v 4X4 with 101,000 miles. I've only put 800 miles on the pickup since I bought it.

The 4wheel drive worked fine last night, had to use it to get home, and it worked fine when I test drove it but, put her in 4X4 today while going down some icy roads and the 4wheel drive slips when you get on the gas. Put her back in 2wheel drive and it seems like it didn't disengage from 4wheel. So I pulled off to the shoulder and put the transfer case in neutral then back to 2wheel drive and try backing up to see if that helps disengage 4wheel drive, but it doesn't want to back up, feels like something in the transfer case is catching and holding it back. So I start down the road and the pickup starts to vibrate when going over 30mph. Vibrates worse the faster you drive, and vibrates regardless of what rpm.

So I called a mechanic friend and described what was happening and he thought it might be an axle actuator or a chain slipping. Not sure what that means, I don't know too much more than how to change the oil. He said it should be fine to drive it slow to the nearest town since I'm not close to home(traveling for Christmas).

So I'm in a hotel room for the night til a repair shop opens up in the morning.

Any help/advice greatly appreciated. Thank you.

 

its probably the cad motor on the axle check the vacuume limes on the axle /transfer case /under hood .

 

doesn't sound like something to worry about..
why?
the front end drive train, mainly used while is 4x4 mode is worn.. the rest of drive train is..so..it might no switch in or out of 4x4 easily.
ok..what do I base this on.
I own 2 4x4 pickups
1 a 1500 gasser, I know a mistake, but I've owned since new..and at times since new..less than 10kmiles, the 4x4 didn't engage or disengage..that truck now has almost 120kmiles..still works the same..if I rock the steering the 4x4 will engange or disengage.
the 2nd truck I bought used.diesel. 4x4. same engage/disengage issues.

rock the steering back and forth..might change things..

-dkenny

 

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

 

Fireman - lets see if I can help a little. There are 2 parts to our 4wd systems, the transfer case and the CAD (center axle disconnect). When you pull the 4wd lever in the cab, two things happen. First, the transfer case is engaged and it uses a chain to transfer power to the front driveshaft from the rear driveshaft. Also, in our trucks, the front axle is split when not in 4wd. When you lock the transfer case, the CAD slides a sleeve over the gap between the two halves of the axle. The axle ends are splined and the sleeve makes the axle complete so you get power to both front wheels (obviously taking into consideration the diff).
The CAD is slid back and forth by a vacuum piston kind of like a power brake booster, not levers, cables or hydraulics. The vacuum lines are skinny little steel lines than run around the frame, axle and engine down low where they are exposed to the elements and lots of road debris. Those lines are notorious for cracking, rusting or getting holes in them. I can't tell from here whether your problem is t-case or CAD but at least you now have the info to understand how your 4wd system works.
On the advice of folks on this board I replaced my vacuum actuatedCAD with a cable actuated CAD called Posi-Lok. I never have to rely on the weak CAD system any more. When I need 4wd, I lock the transfer case, pull the cable to lock my CAD and away I go. Guaranteed 4wd. The kit is about $200and it took me a couple of hours to install.

 

Thanks for the information and advice guys.

The front driveshaft where it goes into the differential was worn out. You could move the shaft around with your hand. When I would back up with all the slop it had it would knock/bind against the diff which was what was making it not want to let me back up.

So the front driveshaft is out until I get home. So when I tested her out after doing this no more vibration but it made some noise when the tcase was in 2wheel and makes no noise when in 4wheel. So something might be wrong with the tcase too.

 

You have a 2002 and therefor should not have a CAD front axle but if you do then you should obviously see the CAD collar on the passenger side of the front axle housing. This will make a difference.

 

Good point. I thought CAD delete was 03 but it's actually 02.5. Just have to look and see which one you have.

Some of the best info and parts are right in your state http://quad4x4.com/

 

The CAD axle was actually discontinued after '01 but its not uncommon to see 01.5's and some few '02's with them. I understand the reason was something to do with Dodge opting to use what they had on the assembly lines. This is the same reason not all 02's have the same extra accessories which other 02's have, like rear cup holders or plastic inner fender covers or hood insulation.