Bad trans or possibly something else?

[Jonnycash]

Hi,
I just picked up a 92 pearlie with a bad transmission, amongst plenty of other issues. It has been sitting for 4 years, since the tranny went.
I fired it up and of course went through the gears.
I got it to go forward, but the engine starts bogging down. Even flooring the gas pedal the rpms never go over 1000. I only did this in the driveway, so I never even went fast enough to make the speedo move.
In R, it acts like its in neutral. I do hear a rattle, but nothing else happens.
This is a rebuilt transmission with about 15K on it before he parked it. He said he was doing 80 on the highway and heard a clunk, rolled it off, had it towed and it never moved until now. Thats all he could tell me about it. He knows nothing about mechanics, so he wasn't able to shed any light on it. He did however give me the $4700 reciept from aamco from the transmission job.
Should I just put another tranny in it? Are there things I should check before giving up on this one? Could it be a bad tourque converter? Any insight would be great. Thanks!
-Jon