I can't imagine this is a common problem but I thought I would share my story. I developed a driveline vibration at cruising speed so on my first day off I pulled it in the garage and sure enough the U joint by the rear axle was bad. When I checked the other joint and it was fine, but I happened to push up on the driveshaft and when I did the whole transfer case moved up and down with it! Upon further inspection two studs that hold the t-case to the trans were gone and all but one were backed way out. Also because the one stud was tight the t-case pivoted off of it and put a pretty good crack in my trans tailhousing. It's not leaking and I got everything tightened up with some new studs and loctite everything seems fine for nowWeird part is I've used my 4wd and checked the t-case fluid recently and never noticed anything off. I'm pretty religious about maintenance and usually anything off about my truck doesn't slip by me...very frustrating. Again probably not a common problem but its something worth looking at.

Actually mine didn't get that bad but noticing a slight wetness at that seam and check the nuts and sure enough the nuts where not very tight.

Was the t-case ever taken out? The reason I ask is because every t-case that I have done that had never been out before had really tight nuts. But ones that had been out before usually were easier to loosen.

As far as I know the case has never been out but a lot could have happened in the 10 years I didn't own it.