I'm stuck in my backyard. 4WD will not engage, no dash light, no front wheel spin, no codes. Haven't used 4WD since winter (3-4 months).

Last month (or so) the 4WD dash light came on at start-up and went out while driving. Don't know how long or how many miles later the light went out. Hasn't come on lately.

Today, I really needed the 4WD after lots of rain. Needed to load up the truck with stuff from my backyard. My backyard is down hill from the driveway (pretty servere hill, esp. when wet, you don't climb it when dry w/o 4WD). So I put the stick into 4WL, no light, figured the light may be burned out. Went down the hill, tried to back-up to the pil 'O' stuff and nothing but tire spin. Couldn't get the stick out of 4WL right away, so I pushed, pulled, got underneath worked the linkage, worked the stick some more, shifted in & out of park/drive/reverse and it finally popped out. Put into 4WH and still nothing but tire spin. It did try to pull once, but made a slight bang like a stick shift popping out of gear.

Checked all fuses, front diff wire connections, etc., nothing amiss.

Front diff. vent tube is puking a little from time to time.

Any suggestions or ideas what might be wrong?

 

Front diff is vacuum controlled, make really sure you are getting a vacuum.

In an emergency, you could always run to the parts store and get some vacuum line, and a mityvac, and manually apply vacuum to hold the actuator in.

Almost sounds like it was trying, but didn't have enough vacuum to hold the CAD in.

 

Thanx! I'll recheck the lines. Your temp fix sounds great, I've got a small shop vac that works on 12V. I'll post the result.

 

If worse comes to worse, you can pull the CAD, engage the fork and cut off a piece of 3/8" fuel line to hold it in place until you have the time to fix the vacuum problems. (hose between the housing and fork to hold it on the engage side).

 

Rechecked vacuum lines. Tried something that worked on an old AMC Hornet that had vacuum wipers. Going uphill wipers would die (no vacuum) so I would push clutch in and rev engine to get a few wipes. So for the truck I put trans in drive & 4WD into neutral, reved the engine, let rpm's die down, engage 4WD and it worked, sort of. Got me out of the yard, but light still does not go on and 4WD will not stay engaged unless you keep pressure on the driveline.

I'm gonna print out both of these replies and keep them in the truck along w/ tubing needed (cheap insurance for when I'm out in the boonies)

I suppose I should replace vacuum lines.

I have one question. How do you get vacuum from the transfer case?

 

Oh, I almost forgot...

THANK YOU patdaly & whitebuffalo

 

A white tube goes into the top of the transfer case carrying vacuum. The red and black lines coming out control the CAD. When one is engaged, the CAD is pulling towards 2WD all the time and the other side is vented. When you shift to 4WD the opposite happens. Sounds like you have clogged vacuum lines (if your A/C and cruise control work fine, then you have sufficient vacuum from the motor). Your vacuum motor may be trashed also since it wasn't used very often I bought one at 1A Auto for $100. It comes with all clips needed for a quick install. Check here for more info:

https://www.dieseltruckresource.com/...d.php?t=198399

https://www.dieseltruckresource.com/...d.php?t=202049

 

posi-lock cable!

 

Sorry for this delayed response. As much as I hate to admit it, work comes first.

Good idea's! Posilock cable. I like the 2 wheel low feature. It's something I'm gonna add.

sheriffav8r - the links have real good info in them. Looks like the vacuum the Dodge is a weak 'link'.

I'm thinking I might have a vacuum pump problem. When I first bought the truck, the PS only functioned when RPMs were up and made groaning noises to boot. After a two hour drive home from purchase, things loosened up and most of the groan was gone. Cruise works, but sometimes it gains speed after setting. AC works only when driving, not in idle (may need charge). All points to: I need to check vacuum.

What is the correct inches of Hg at the white supply line to transfer case?

 

if you're chasing vacuum probs on the CAD, what helped me was to unbolt the CAD and let it hang. then do whatever you're doing vac wise and shift from 4wd to 2wd. if its working, you should see the fork sliding back and forth. Its not uncommon for the CAD itself to go bad, of course weak vacuum supply will cause the prob too

(i used to have a 2nd gen with a CAD and a jeep with one)

glad you got it out of the yard