After I take the truck out of 4WD, it takes FOREVER for the light to go out. Usually several miles, and it will sometimes flicker out them come back one, and periodically come on for no reason.

Is this a "known issue" with a known (and hopefully easy) fix?

This is an irritating little quirk :P

Thanks

 

It means you have a loss of vacuum, and that actuator isn't disengaging the switch fully. Do you also happen to have the thing where if you have the heater on out the front dash vents, and you get on it full throttle, it switches to the defrost? If so, this is a definite vacuum loss in your system.

 

Yep, I have that too. Where's a good place to start looking? I replaced a faulty check valve that was on the manifold, passenger's side, right under the TB. This appeared to help not at all. It also idles a little rough when cold, which I would bet is vacuum too.

Where's a good place to start?

 

Do a search for vacuum leak on this forum. There have been tons of posts about this issue, and lots of people have posted where they ended up finding there leak at. It can be a tough one to diagnose for sure.

 

OK, cool. Thanks for pointing me in the right direction. Off I go into Vacuum System Hell!

 

Start with the simple stuff. Check that the vacuum lines going into the actuator on the axle are fully seated. Follow the vacuum lines out and look for holes. Check also that you have vacuum tubes inserted into the sides of the intake manifold. Make sure those hoses aren't crack or old. There is also a vacuum elbow under the battery tray if you have cruise control, and it is known to leak too.

 

You say cruise control... hmm... I noticed that my cruise is weak, and can't even kick it down out of overdrive when it would need to and just slows down. I think I'll check under the battery try first.

Thanks !

 

http://www.4x4wire.com/dodge/tech/solid_axle_cad/
http://www.dodgeram.org/tech/repair/..._engagment.htm

it could be vac,
or faulty/sticky/slow cad,
or faulty light switch on drivers end of cad.
put it up on 4 jack stands, motor running, in gear, vac operatiing, and watch for cad to engage/disengage passenger axle/tire. don't assume light is correct.

 

I wasn't able to visually or audibly detect any vacuum leaks. Is there something I can spray on the line/fittings that will change the engine idle to let me know there's a leak there? I know there's something my father used to use but I can't remember what.