[firetruckredram]

I have a 99 dodge 2500 cummins. When I pull the stick in 4x4 my truck is not going into 4x4. The front drive shaft is locking in and spinning but it is not doing anything at the front axle. The 4x4 light is not coming on either. Any idea what it could be. Could it be the hubs. I looked I only can find one vaccum line that comes off the axle and it is hooked up and looks fine. Any help would be great thanks.

 

[Road Dog]

The 4x4 indicator is controlled by a switch on the CAD (centre axle disconnect). A vacuum line from the transfer case controls an actuator that moves a fork that connects the axle. On my truck the vacuum line touched the exhaust and leaked. Hard to see too.

Or the actuator has failed.
Or the fork has seized.
Or there's no vacuum from the engine.

 

[firetruckredram]

thanks for the info does anyone know what to do to check some of these could be's that may be causing my problem.

 

[wbtatb]

Get a vacuum pump from the autoparts store remove the vac line from the t-case attach the vac pump to the line going to the front axle and see if it moves the vac canister. Also there should be two lines going to the front axle. The other thing you can do is pull the line and try to low through it if you can your line is bad other wise look into the vac canister first then to the t-case. I had hung some rocks up under my truck and damaged the canister, had to replace it.