BigErksG2

Well the only time you find out 4wd isnt working is when you need it. With the 2ft+ of snow we got hit with over the weekend, 4wd is a necessity to get in and out my driveway. 4wd was working fine yesterday but I put in into 2wd in a home depot parking lot because I was making sharp turns and it was asphalt (didnt want 4wd binding up). I got back on the roads that are mostly 6 inches of packed snow and I put it in 4wd but my 4wd light didnt come on and it was obviously only the back 2 tires spinning. I'm guessing a vacuum line came off for the electronic hub lockers but before I crawl in the snow, are there any other common problems that it could be?

Thanks in advance.

JD730

If you have a vacuum gauge handy it will make finding the problem alot easier.

But, somewhere, somehow its not getting vacuum. I would start at the axle and work my way back, up to the T-case and then up to the where the vacuum is supplied under the hood.

BigErksG2

Can anyone describe where the vacuum line is located on the axle?

runnamuck

they connect to the CAD autuator (oppisite side control arm mount as the diff), run up the control arm, down the frame, across the crossmember, up the the switch on the t-case then up the top side of the tranny to the vac. supply. well this is what they do on an auto anyway.

blackimpala

I think its on the FWD pass side of the Axel, look for a round thin canister this is the actuator motor it will have a rubber connector on it for the vacuum.

Floyd

sabreson

On my 97 the vacuum pump is on the drivers side right behind the timing case, next to the psteering box. My vacuum line came disconnected from the pump, same symptoms. In any case, I would trace all the lines coming from the vacuum pump to the CAD and t-case for leaks.

BigErksG2

I'll see if my cruise control works on the way home. If it does it at least narrows my search to the transfer case and axle. Thanks guys.

justme-

if the vac line came off the pump you would have NO vac at all- no brake booster, no hvac door control, etc. Very noticeable.
if you can;t find a leak, pull the switch off the top of the xfer case- they have a habit of sticking- just a steel ball in there that is moved in position by the shift shaft in the t-case. Unscrew it and free the ball if it's stuck. Most common issue after a faulty vac sol.

lgp9999

Mine has hydroboost. I thought all Cummins Dodges had hydroboost.

siebertl

Go with a posi lock and don't worry about it again.

http://www.4x4posi-lok.com/app_dodge.html

BigErksG2

Thats a nice kit for $85 bucks. Turns out, one of the vac lines disconnected where it goes from a plastic line to a metal line under the truck. My external lubrication system had the boots a little slippery under there and im sure projectile slush from all the snow didn't help. Thanks guys.

arcticcat12224

Ford lockouts are the way to go.....

justme-

hydroboost was not available until 1998 I believe - and it is not the best system overall- I have it on my Chevy 3500 dump- no engine no brakes. That's a fine wake up with a load.

Posi-lok SUX!!! Stay away!!! I have it PITA to install (directions are lacking and inept) and it strips out the threads in the locking end (handle) of the cable way too easy. Vac motor was $350 when I needed it, posi was way cheaper- I'll be going back to stock motor prolly this summer after 4 years on a posi-lok - I hate it!