2nd Gen Non-Engine/Transmission no 4x4?

[RFyfe]

My 94 2500 decided the other day to not work in 4x4. The drive shaft is powered to the front axle, but no go from there. Any ideas.

 

[PC12Driver]

The front axle on our trucks uses a central axle disconnect (CAD) setup to lock/unlock the front axle. Basically, the long side of the axle (passenger side) has a break in the middle between the differential and the wheel hub. The two axle shafts are splined, and when you engage 4wd a collar is pulled between the two halves (using vacuum supplied by the vacuum pump) linking them together, thus "locking" the front axle. If the collar isn't fully engaged, no 4wd.



So your problem could be in the vacuum system of your truck (do your HVAC vents work properly? They're also vacuum controlled). Check for breaks in the lines between the axle and the transfer case and between the transfer case and the manifold. Or the CAD mechanism could just be stuck.



CAD setups aren't known for their reliability. Some folks replace the vacuum setup with a cable.



If you need parts for the CAD (Vacuum motor, collars), Quad 4x4 can hook you up.

 

[RDelissen]

the same thing happened on mine, but after cleaning the connections (since the 4wd light would stay on for a while after disengaging the 4wd) and retightening the vac hose it worked flawlessly again

 

[RFyfe]

oops, my brother left a vaccum line undone. Thanks for the help though.

 

[RFyfe]

oops, my brother left a vaccum line undone. Thanks for the help though.