Hello,My 4 wheel drive will not engage I noticed it Saturday while helping Brother in law move.I recently had it in for repair of cam cover gasket wondering if there was somethingthat might have been disconnected during the repair causing this. I have a 2500 2001 sport quad cab.Thanks in advanceDavid

Check you vacuum lines for the CAD system. There is a vacuum line that runs back to the transfer case then back forward to the CAD system on the backside of the axle.

the vacuum line coming off the vacuum pump, (in front of the power steering) leading up to the firewall and t-ing in near the valve cover. this line is most likely cracked or forgot to plug back in simple push on fittings. if this is the cause the a/c vents wont actuate either.

Thanks, I found a vacuum line off behind the master cylinder that goes down behind the block did not see where it came from but hooked to a spot that was capped off on a tee. Anyone have a picture off the routing? Looks to be loose at the back of the block as well.ThanksDavid

Sorry there is very little on the vacuum hose maps for Dodge Cummins trucks... But basically there is very little if anything that uses vacuum. HVAC which is in the passenger side, brake booster (for earlier trucks), and CAD axles for 2001 and eariler trucks... Like my truck (2002) the vacuum is for HVAC and Exhaust brake.

If for some reason it turns out to be the actuator I highly recommend the posi-lok. We have used them on several chevies with great results. http://4x4posi-lok.com/