My 4x4 wont engage. the red and black lines which lead to the tcase are fine and the two green and white wires which run up behind the distributor are just hanging there. Where do the green and white wire go to?

 

One is vacuum supply, the other is just a vent hose. (I don't recall which is which.) Having no vacuum supply would certainly explain why your front axle doesn't engage.

 

i have the same prob. mine wont engage, it used to perfectly, then it would take 5 mins... then 10 mins.. and now nothing so i think the motor might of went out on mine i dunno.

 

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

common problems include vac leaks, sticky/rusty diaphragm shaft, worn bushings causing misalignment, and burrs on the splines making the collar too tight.

the fixes are mostly simple. you can fix it annually or replace the whole pile of **** with a posilok.

 

green is fine but the white line is the vac supply line, if its "hanging" your getting no vac to the cad.

supply the cad with vac and well go from there; that likely will solve the problem though

 

could be a steadily deteorating vac line. verify that you have around 17" vac at the cad.

i believe the red line should have vac in 2wd and the black should have vac in 4wd. (or vice versa).

thats the most likely cause but could be a bad shift collar or jacked up axle shaft splines as well as the shift motor. my ram has 170k on it and all those components are in great condition

 

I have a 2000 dodge ram 1500 4*4, I have replaced the actuator, and the 4*4 still doesn't work, and I have also noticed that the a/c vents acts funny as well like they open and closes... where in the vac lines should I look to find the problem, and does the two problems have a common vac point that I need to look at???

 

Do a search of this forum for "wild vents" and you'll find everything you need to know, and then some.

 

I put a perm-lok on mine to make it foolproof. Now it's always ready to go into 4WD as the collar is permanently slid over.

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

 

I didn't feel this deserves its own thread so I'll necro this one. Also, I'm not putting this forth as an example of superb mekaniking. Rather, this is a Q&D just-get-er-done white trash approach (I can say that because I identify as white trash). However, I will say I did this on a '99 about five years ago and AFAIK it's still working (the owner woulda called me if it weren't, she's only a few miles away).

I just did this for the second time on a '98 last night.

SYMPTOMS:
-extreme frustration and annoyance combined with excessive head scratching because everything appears to work.
-all vac lines intact and not clogged
-16 to 17hg at vacuum switch on t-case
-CAD actuator works as it should
-vacuum switch bench tests fine

And yet once put together no vacuum gets to CAD, thus no 4wd

THE CULPRIT: the rubber 4-way female connector (geez, in any other context that could sound kinda fun) at the t-case just gets soft with time (it happens.....) and leaks (it also happens....) vacuum

You might be able to verify by squeezing the rubber connector while it's on the vacuum switch. If you suddenly start to get vac at your red or black lines the rubber is responsible. Also, if the truck has a stock-ish exhaust you may hear vacuum leaking at the switch. Note the switch need not be installed for testing, I reco removing from the t-case and reinstalling the rubber connector. This way you can pull it a bit forward and down, closer to you. You can operate the plunger with your thumb.

The Q&D solution to keep everything functioning as OEM can be to increase the OD of the male protrusions (I think there's a pill for that....?) for a tighter fit (ahem).

I keep a selection of heat shrink butt connectors so I just lopped off the ends, slid over vac switch and shrunk. This is almost too thick, in hindsight a couple layers of standard heat shrink tubing might be better.

I started with just the vac supply but still wasn't getting vacuum through the switch so I did the supply and the unlock (red) and the lock (black). I didn't bother with the vent

Again, I'm not saying this is a GREAT approach, but it works and for me required sourcing zero parts on a Saturday night


oh, I also had to lop off the two plastic locator pegs from the switch so the rubber would fit, but I just scribed the switch body where they would have been