Post Mud Bog Drivetrain Noise

I buried myself in a mud bog a couple of months ago on a camping trip, I was stuck pretty bad. Spent about half an hour spinning the wheels while trying to yank it out of the hole with a buddy's 4X. Here's my problem now; If I goose the gas enough to spin the rear wheels on loose gravel or other slippery surfaces while in 2hi (doesn't do it in 4hi or 4lo) I get this strange type of grinding/zipping noise coming from the drivetrain somewhere, and can tell that something is slipping somewhere, maybe the transmission or transfer case, causing the wheels to not get their full torque from the drivetrain. Everything is fine on normal dry pavement.

Any thoughts as to what might be wrong?

'01 sport, AW4 (i think), NP231, C8.25, 105,000mi

U-joints? When's the last time they were changed?

check your engine/trans mounts, I'd couldn't keep jobber mounts in mine!

I took in to AAMCO to have it checked out. They think that it might be the TC, but they want $1300 to pull it out and take it apart just to see whats wrong, then if they found something it could cost upto $800 in parts. The kicker is that their not even sure that it is the TC.

I've read some posts that talk about the drive chain in the TC stretching out, but the symptoms don't seem to match up i.e. loud popping noises. I checked the linkage to make sure that it was fully engaged in 2hi. I also checked the all the u-joints. Everything seems OK.

If anyone has any ideas on what could be causing the loud zipping noise I'd like to hear it. BTW if there's any sparkys out there the noise is similar to pulling MC through a steel stud; not really a grinding noise, but more of a zipping.

Thanks in advance.

change the oil in the transfer case and see how it looks. Make sure it's full before draining!! Could have contaminated the transfer case oil...

If they want 1300 to inspect a transfer case, just buy a new one and throw it in yourself to save the cost/hassle!!

FYI, reman 231/242 t/c cost $629 from Qtec. Up to $150 at auto wreckers, usually $50/$75 at a pulla part. AAMCO hasn't changed a bit in the last 40 years. Not a good company to deal with.