My son recently bought a 99 2500 with the Cummins, auto (a 47RE, I believe that was recently rebuilt). The PO said whatever engages the front axle quit working, so he installed one of those hand throttle cables that screws out (like on the pump panel of a fire truck, that you turn out to throttle up the motor). Naturally since we've gotten a load of snow over the last couple days it's not engaging again. I crawled part way under it, you can see where it ties into the front axle with what looks like a factory cable and what looks like a vent line running up to the frame? We're going to try to dig into it tomorrow after work, I thought originally it was some sort of vacuum that pulled it in? I see there are kits to rebuild the pump and what looks like an actuator, we'd like to get it back to stock (and working!) but I'm wondering where it is mounted, if anyone had any experience?
And is thee a way to adjust the linkage to the transfer case? It is a real pain to get in, and if you don't get it just right it will pop back out.
Any suggestions or links appreciated!
Al

You are correct in that it works off of vacuum. There is a switch on top of the transfer case that has 3 lines going into it. One should come from the vacuum source, and the two other go to the front differential via steel tubes bolted to the frame. This would be the first area I would check in order to get it back to functioning in stock form. If it's not going into gear very solid and popping out I would expect the worst and figure there is something wrong internally with the transfer case. The shifter doesn't have any sort of detents in it so the only thing that determines where it sits is the fork inside the transfer case.

The vacuum pump should be on the passenger side fender well. It should provide vacuum for your cruise control as well. It should provide vacuum to the switch and then to the actuator mounted on the front axle.

Some one installed one of these http://www.4x4posi-lok.com/app_dodge.html . So you will have to figure why its not working.

The transfer case shifter has a pivot sleeve and bushing that gets rusted to the bolt and the shifter will not work right. You can try lubing and working it to see if it will help. If not you will have to pull the shifter and get it freed up on the work bench.

Recently did the exact same thing on my 2000,the vacuum actuator was quite pricey, 180 bucks from a friend at NAPA. Avoid the dealer, they wanted $220. Do your best to save the case since a new one is not included. You only get the internals and new bolts and washers.