Before I take this in wanted to get some opinions on what it could be. When driving the truck normally I have noticed when you accelerate the heater switchs from normal vents to defrost vents then will switch back. I have noticed since this has started doing this the 4 wheel drive will not lock in. I start the truck and with it in park I pull the lever to 4 high and then put it in drive but the 4 wheel drive does not lock in and the light does not come on like it use to. Only the rear wheels work.

Thanks

 

vacuum leak.
read this. http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm

 

This would make since then, about 5 months ago I took it in and had all the fluids checked and changed and they had to replace a gasket on the 4 wheel drive unit because it was slightly leaking they said. Bet when they did this it did something to the vacum line. I noticed the switching of the normal vents to defrost vents right after I had the service done. Glad to know this because now I can take it back down there and at least kind of know what it could be.

Thank you for your help.

 

+1 def. a vac leak....and you have the "wild vents" which is also vacuum caused.....


look into a posi-Lok on summit