Drive shaft turning/wheels not pulling.
 

After fighting, swearing and pulling my hair out at the way over complicated 'push-button 4x4 the wave of the future!' nonsense I thought I had it fixed by replacing all the vacuum lines, actuator, transfer case switch, axle cable and confirming diaphragm was good. I even put it in 4x4 after noting the position of the front drive shaft and pulling forward a few feet and seeing it was indeed moving and I couldn't twist it with my hand. Last night here in KC we received another round of snow. I confidently thought 'oh cool, I can have fun with my 4x4!' and pushed the button. When I go to reverse out of the parking lot I move 2 feet and stop-back wheels spinning. I pulled forward and then tried backing up again-rear wheels spinning. I opened the door and looked down at my driver's side tire and it's doing nothing-not even remotely trying to turn. What in the world is going on if my drive shaft is turning and feels locked in but it acts like no power is going to the front? Bad weather is the reason I bought this gas guzzler to begin with and it's let me down. Sad that when I got into my old battle ax '93 Escort LX wagon it busted through the same snow without any problems. I'm thinking of seeing if I can trade even up for a small car because I'm tired of working on this truck. I love the ergonomics and layout-and driving it is a pleasure. However when it comes to working on it the darn thing is a nightmare. I'm definitely experiencing the love/hate relationship all owners seem to have with what really is an SUV pretending to be a truck. If people weren't smart enough to manually pull the old style transfer case lever that never failed then they probably shouldn't be driving. Rant finished, thanks for your time.

Maybe the coupler in the passenger axle tube isn't engaging? That was my problem, the gear teeth were chewed up, not allowing the collar to slide down and engage the front axle

That's what stinks about the electronic stuff. I have the little bit older lever one for my truck just because I don't want to deal with the aggravation.

That's what I can't figure out-if I can't turn the front drive shaft by hand in 4x4, that should mean the axle is engaged.

Did you lift the front end to see if the tires spin in 4wd? With 4x4 on they should be locked...

If the t case is in 4wd, the front driveshaft isn't gonna turn by hand regardless of what the front axle is doing. And it will spin when you drive, but not be turning the front wheels.

I have a posi lock setup, so I can engage the front axle separately from the tcase. Without that, you'll need to jack up all four wheels, engage 4wd and see what happens.

If the tcase engages, and locks in the front driveshaft, but the front wheels don't turn, the problem is in the front axle disconnect
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I checked the vacuum lines-and I have oil in them. It's not transmission fluid either-but engine oil. I replaced the PCV valve over a month ago. I tried the 4x4 for kicks and heard it slightly grind-there just isn't enough movement to fully engage but just enough to trick the computer into thinking everything is where it should be. I think I'll save myself some grief and future pain by getting rid of that awful vacuum system and putting in a posi-lock. I've seen the thread for making your own homemade one which is fine and dandy but I think I'd rather have the stainless steel one that hooks directly into the front differential. Probably be a spring project because I have to replace the seal in the differential for the pawl that locks it in. Apparently these seals are another weak link in this awful system.

With the grinding, you should look into maybe rebuilding gears if the manual lock doesnt work

Try to manually engage the front axle to see if it will engage fully. The grinding might have damaged the teeth on the coupler, and not allow it to slide down all the way.

With the front wheels in the air, and the truck in 2wd, unbolt the housing on the passenger axle shaft that the cable goes into. Pull the housing out, while spinning the passenger front wheel. If it's engaged, the driver side will spin the opposite way.

Mine wasn't engaging fully. It would being to couple, then slip and free spin. I ended up having to replace the gear

https://cimg2.ibsrv.net/gimg/blazerf...4e0343d908.jpg

The left one was chewed up, not allowing the collar to slide onto it

Thanks for the heads up cleburne. I really hope this isn't what's happened-the weather has been cold and wet all month and I don't have a garage. Either way, I have to replace that seal so having a messed up gear would make the hassle more worth it in an odd way. Not sure how long the PO ran it like this-I do know last winter I used it a couple of times and it did engage, just not all the way as I'd hear a 'pop' when pulling a hill as the gear would slip. Now it doesn't engage at all. Engine oil in the vacuum line has to mean a leak somewhere but I haven't found it.