4WD not engaging
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Amateur
Joined: Jun 2006
Posts: 33
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4WD not engaging
Trying to fix the 4x4 that was not working when I bought the truck. I have a vacuum line off right where the steel lines to back to plastic. One line is missing the boot. Anybody know where I can buy that?
Also does the CAD get vacuum from the engine or does it come from the Vacuum motor on the CAD???
I do have a vacuum leak on the engine somewhere cause when I put a load on it or go up a hill my A/C will switch from the vents to defrost till I let off the gas.
I started truck and put transfer case in 4 low and I dont feel any air on the line that is off.
Also does the CAD get vacuum from the engine or does it come from the Vacuum motor on the CAD???
I do have a vacuum leak on the engine somewhere cause when I put a load on it or go up a hill my A/C will switch from the vents to defrost till I let off the gas.
I started truck and put transfer case in 4 low and I dont feel any air on the line that is off.
Veteran
Joined: Aug 2009
Posts: 461
Likes: 0
From: Illinois
The vacuum line to the CAD can be replaced by a couple of small rubber hose. I just replaced that boot with a couple vacuum lines. Might try the junk yard if you feel lucky but not much chance they will be in good shape or even existant. The CAD gets it's vacuum from the motor but doesn't get vacuum until you engage the 4WD. As for the "crazy vents" I think we all have that problem. I have replaced EVERY vacuum line in my truck and still have the vents go crazy under a load. Could be the check valve on the front of the Throttle body that everyone keeps talking about but I havent gotten around to replacing that. Procrastination is a S.O.B. HAHA
Hall Of Fame
Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
note several tabs here. it contains everything you need.
http://www.dodgeram.org/tech/repair/..._engagment.htm
most problems are very simple and can be repaired with just a little effort and little to no money. spline alignment is probably the hardest...
edit - vacuum originates from the 2wd/4wd switch on top of the t-case, and connects to the cad. vac on one line = pull collar to the passenger side (disengage). vac on the other line = push collar to the driver side (engage). any vacuum hose or pipe that does not leak is fine, but note that any lines under the truck are subject to damage from all the crap that you run over, so routing them over the top and straight down along the vent hose is a much better place than the stock location of along the bottom of the cross member. mine were chewed all to hell.
after you get tired of repairing the cad (takes about 3 times), look into a posilok cable system.
http://www.dodgeram.org/tech/repair/..._engagment.htm
most problems are very simple and can be repaired with just a little effort and little to no money. spline alignment is probably the hardest...
edit - vacuum originates from the 2wd/4wd switch on top of the t-case, and connects to the cad. vac on one line = pull collar to the passenger side (disengage). vac on the other line = push collar to the driver side (engage). any vacuum hose or pipe that does not leak is fine, but note that any lines under the truck are subject to damage from all the crap that you run over, so routing them over the top and straight down along the vent hose is a much better place than the stock location of along the bottom of the cross member. mine were chewed all to hell.
after you get tired of repairing the cad (takes about 3 times), look into a posilok cable system.
Last edited by dhvaughan; Jun 13, 2010 at 10:12 AM.