I had that same problem and it was my planetary gears were shot

 

Sorry guys I never ended up snapping any pics. Once I tore into it there was no stopping. I called a friend Tuesday morning after I had done the small stuff and he got there about 10:30. We each did a side and had it down around 1:00. We seperated the t-case from the junk because we took them down together and than put my "new" trans up and mated the t-case under the rig. We had it all back up around 4:30 and than went to pickup a new trans filter and 12 quarts of fluid. After dropping the pan on the "new" trans I was very happy. it had a little bit of very clean fluid in there and the magnet was clean. I swapped the filter anyway and filled it up and off she went. I've already got 200miles in such the swap and all is well. The trans I put in is only 9 months newer than mine and if 37,000 is all it's got thats great mileage. All in all total cost $866 for trans, $62 for 12qts fluid, and $13 for trans filter. $944 sure beats the hell outta paying a stealer or rebuilder.