90 Auto Trans PLEASE PLEASE HELP

This is my first post, as ussually i can find what i need under someone else's post, however I am stuck. I have a 90 supra NA automatic, and i rebuilt the engine last year. Well maybe not totally, but to the extent that i can afford. At any rate the engine is running well, aside from a few small problems, but my transmission is going crazy. I have been up to my armpits in ATF for 3 weeks now, here is what happened:

The transmission was having problems with slippage and no reverse gear. Bought a used trans, along with another i had lying around from an engine donor car. Suspected the valve body, and switched it with one of the others. After bolting it back in, A very arduous process i might add, i had No Neutral and no reverse. Ok, took it all back apart, nothing looks burnt or fried, and the clutches all look new, although this is my first auto trans autopsy. Now, all reassembled, and with the gear selector in neutral, the drive shaft is not free to spin. I understand that P N and R are all mechanical, and not controlled by the computer, so it should spin free at this point, correct?? I followed the TSRM, although i didnt dissassemble all of the smaller clutch components as the ones i took apart looked fairly new. As per the instructions i checked all the clutch mechanisms with compressed air, and could hear each of them engaging and disengaging.... properly? sounds good anyhow. I must be doing something wrong, But i cant figure it out. I dont want to bolt it back in until i can get it to spin free in neutral and it would also be nice to see some reverse action. Everything inside checked out to the tolerances, as best as i could measure without the SSTs. I am really stuck, any help would be greatly appreciated. I have the time, as on my last dissasemble i broke the valve body gasket and now i need a new one just to install and test. Also i would like to add that this is my only car, and i was recently laid off, SO I AM DESPERATE for information that can get me back on the road.

Sorry about the length, thanks for your help. John

Yikes! I *think* you are over-complicating the problem, you have have misaligned the shift linkage...this is usually the problem after a lot of A/Ts are installed. I hope it's as easy as that for you. Make sure the linkage is lined up correct

I dont think thats it, right now i have the trans out of the car and it doesnt spin freely like it should, is like its stuck in gear, the shift linkage isnt hooked up at all, seems to me something has to be stuck? :mad: thanks for any help