Tranny problems, help!

[Long Roof]

O.k. I'm feeling a little baffled at the moment. The family and I took the Jimmy out for a drive last night and on our way home we stopped to pic up some food. I waited outside with the engine running and put it in park. When I went to drop it in gear to leave it lurched forward as soon as I moved to the reverse detent. I didn't think much about it at the moment but once we got down the road it wouldn't shift out of 2nd gear. I pulled over to take a look and found out I have no reverse or neutral. We took of down the road again and now I only have 1st. We drove it home and I looked at it this morning in the garage. The shift linkage is just fine. I started it up and as soon as I drop it out of park it wants to go forward. What gives?

The tranny is a rebuilt 350 turbo and it was recently installed by the previous owner.

Any tranny experts have any idea what is going on?