Loud bang in 4x4, than dragging feeling
 

2000 Jimmy, 240k miles. Today I pulled off the side of a paved road onto a grass shoulder briefly, and we've had a lot of rain, so I put it in 4hi before pulling over just in case. When I pulled back out of the grass after less than a minute, I forgot to take it out of 4x4, went to turn around at the intersection maybe 30 feet away, and just as I started the turn I heard a loud bang that sounded like my right rear tire blew out, and there was a dragging feeling which I've felt before when trying to drive on a completely flat tire. So I slowly completed the u turn, got out to check and all tires were fine. So I got back in and when I hit the gas to cross back over the intersection (straight line) I could feel a strong dragging, like something was holding the car back. That's when I remembered the 4x4. Soon as I hit the button it went back into 2wd and drove off perfectly fine, no more dragging. I came straight home, just a few miles, and haven't tried the 4x4 again. Don't want to risk any further damage. And just to be clear, it was a loud BANG! Not a clunk.

I didn't hear any grinding or other noises after that bang, just the feeling that the car was dragging/being held back. And that stopped as soon as I put it back in 2wd. I did use the 4x4 a couple days ago briefly on a very muddy road, and had no problem. I've owned this Jimmy since it had 80k miles on it, and the transmission was completely rebuilt back before 200k, maybe around 160k. But I'm just guessing this is more likely a transfer case issue, not transmission? Help?

I would like to repost to the drivetrain section since I'm not getting any replies here. I don't see an option to move or delete the post. Can an administrator do this so I don't end up double posting?

It is customary to wait at least 24 hours before even bumping a thread let alone asking for it to be moved... It's still nice outside and many of our members may just be out enjoying time with friends & family, not stuck inside on the computer waiting with baited breath for someone to post a question that they could help out with.

As far as your problem... Are all of the tires the same size and inflated to the same pressure?

Have either of the differentials ever been replaced? If so, were the gear ratios verified prior to replacement? If you don't know, have you verified the ratios (google is your friend here)?

Same size tires all around. I had a flat fixed couple weeks ago and had them check all tires for even pressure. Haven't checked myself since then because nothing has looked low. Differentials have not been replaced since I owned the vehicle. Assuming they weren't replaced before I bought it since it only had 80k miles when I bought it, and I've never had any problem like this before. I know 4x4 while turning on dry pavement can cause binding, and hopping, but not sure about the loud bang. And why it had that dragging resistant feeling when driving off in a straight line, after the turn. Can the front drive shaft break, or something in the transfer case? I'll put it in 4wd and test again tomorrow if that's suggested.

Are both of your front axles in tact? I had an axle break before and it was an extremely loud bang.

Did you do a visual under the truck?

I would try it again see if its still dragging.

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Yes try it again. Sooner or later your going to have to

Your 4wd could not have been fully engaged as well.
I had an issue with my first gen where it would try to engage its self partially while going down the highway and would cause an extremely loud bang and almost make the truck jump along with a hum/drag for a couple seconds and I would push the 4wd button and it would stop.
Turns out it was my encoder motor being bad along with a vac issue in the system causing it to try to engage randomly. (I ended up just unhooking it because I got rid of the truck shortly after)

Sorry so long to check back in, but wasn't having any issues with the Jimmy and been real busy. I never put it back in 4wd to try. I did look under the vehicle and both cv axles look and feel fine. Nothing obviously broken or loose. But today it has started making a clunk clunk clunk noise at low speed, and I can feel it under my feet. Seems to disappear when turning right, but not when turning left. Now, I've heard two different things about the front drive shaft. One person says the front shaft doesn't turn unless it's in 4wd. Another says it always turns, just isn't engaged inside the transfer case when it's not in 4wd. So I'm wondering about that for one thing. And also how to check the drive shaft and joints. It has just a little play when twisting back and forth. Is that normal? Or do I need to check for play up and down, rather than twisting? Watched a video but I was unclear on exactly what is normal and what isn't.

Of its not engaged it should turn freely