I've read somewhere (here, I'm sure) that the axle engagement is somehow vacuum actuated. I can't find a thread that specifies the potential problem(s) and the fix. Can someone run me through how to diagnose and fix this? Coincidentally (or maybe not), I was easing down a dirt road yesterday AM around 0-dark-thirty and ran over a stick about the size of my forearm that flipped up and smacked the bottom of the truck. It hit hard enough for me to stop and figure out what it was. I was in 2WD at the time. When I went to put it in 4WD yesterday afternoon, no dash light indicator, and no engagement at the wheels. The transfer case is engaging. Thanks in advance for any help!

The obvious would be to thoroughly inspect the areas where the vacuum harness/wiring from the t/case to front axle runs.
If nothing obvious there, it's likely the vacuum switch on the t/case. They were a problem for years...

Thanks, Superwrench! The black vacuum line at the transfer case was disconnected. I guess that stick probably knocked it off. I looked at the front axle yesterday afternoon in the woods, but didn't have good light. I obviously didn't look toward the transfer case, because it was...obvious. I suppose I should have looked again this morning before creating this post, but I guess I thought it would be more complicated. Thanks again for the quick help!

They make a cable setup for the front axle. I put one on my truck earlier this year and I love it. If you want 4wd you'll have it. Cost me like 150.00 and about an hour to put it on. I plugged the vacuum at the transfer case. The cable looks like a PTO cable from a dump truck.

Thanks for that info, Kenworth. If/when the vacuum system takes a dump, I'll certainly go that route. At that point I'll probably wish I hadn't waited, but it's tough to fix something that ain't broke (yet). I see a couple different ones on-line, but this one seems to be the original: http://4x4posi-lok.com/app_dodge.html Saved in my favorites. If there's a better system out there, please let me know.

The cable conversion is nice, but the cable can seize up just like the vacuum hose can break. Choose your poison. The NICE thing I like about the cable is it gives you the option of 2WD LOW (shift the transfer case to low, but don't engage the 4wd cable), which is really nice when you are moving trailers around in tight spaces, slight grades. Won't hamper your steering like 4wd does.