T-case noise?

My Xj is a 2000 with the 231, I had my Jeep in 4 high for a few miles on a dirt road today and when I shifted it back into 2wd my 4wd indicator light went off but I could tell by the t-case whine that I was still in 4wd, I drove slowly for 20 yards or so so then I heard a loud clunk through my floor board and my Jeep sounded like it was finally back into 2wd were it should have been.
I then put it back into 4wd and tried to disengage it a second time and the same exact thing happened.

I had a shop install a AA HD SYE a few weeks ago and am wondering if the two are related. Before the install my Jeep went in and out of 4wd without a noise and did it as soon as I pushed the lever down.

Any ideas on what the problem could be would be greatly appreciated since my wife was along for the ride today and started wondering if modifying "our" Jeep was such a great idea.

thanks
Silver Bullet

Were you on dry pavement when shifting out of 4wd, or in a turn? Sometimes the t/c has some "bind" built up when in 4wd for long periods of time. Mine did the same thing, but I had the donut spare tire on (different diameter tires will do the same thing-except much worse). If you put it in reverse and back up a few feet while still in the dirt just before shifting out of 4wd, it normally relieves some of this stress and it is easier to shift out (without the bang).

I was on an ice covered road at the time going straight. I put in four wheel yesterday with no problems or noise on a muddy road, I'm hoping it was an isolated incident.

Next time I will try backing up a few feet first before shifting out, to hopefully avoid the same thing happening.
thanks
Silver Bullet