More than likely you didn't break anything. It sounds like it's just stuck in 4H from pressure. Jack up the rear axle and put the transmission in neutral. Then it should be able to be shifted out of 4H. It just may take some force. Don't be afraid to put some muscle into it to get it out of 4H and into Neutral....the transfer case is strong and you won't break anything by doing that.

Not necessarily broken yet, but will be if you continue to drive and corner in 4WD.

It is called axle wind up. The reason is that when 4wd is engaged, you are driving front and rear axles at the same speed all the time - when you corner the front and rear must be driven at different speeds as they take a different track. This causes tension built up within the whole of the drive train and if then, tension is not released it keeps on building up until something gives. Usually something small, delicate and very expensive!!

Try jacking one wheel off the ground, vehicle choked as the handbrake needs to be off.. If it is wound up it will unwind rapidly so stand clear.

Alan, it looks like the front was wound up just a bit. I figured it would have been much more. Turns out my hubby was able to muscle it out of 4H before he left for work this morning and didn't tell me. Thank you Alan, and thank you Gearhead for your excellent answers. I can't choose one over the other as they both helped.

Lesson learned here. (Always check the lever and lights before heading out.)

Thank you for your info, James, but the whole issue was that I couldn't "just" shift it into 2WD.

I dont believe you damaged anything serious here. If the truck is stock and you didnt install lockers in the front differential. The stock differential is limited slip so even on dry pavement you can run 4 high it allows one wheel to spin freely for so many revolutions before engaging the other wheel a few turns wont do that. that is why the limited slip is their to allow this. I believe these trucks have on the fly 4x4 when you push the button or pull the lever the 4 wheel light blinks till engaged or dis engaged. The most likely issue here is the actuator that engages the transfer case. they are very sensitive to heat and cold and do fail. that is where I would start especially if you dont engage the 4x4 that often. and in some cases just shifting into regular 2 wheel and driving slow for a bit might kick it back over. other things to look at are the linkage or wiring to the actuator possible fuse if it has one.

I drove five miles on dry pavement to town. A few turns were involved. Yes, I could tell something was funky about the way the truck was performing, but it didn't even occur to me to check the indicator on the floor. (Screaming kids, etc...)

Now I can't get my 98 Chevy c1500 1/2 ton out of 4H. I tried shifting it while in drive, neutral and reverse to no avail.

Any ideas as to what I broke?