How to check out a used tranny

[XXBULLETSXX]

As the title states, I need to find a way to inspect or check out a used straight drive. I'm trying to buy a T5 tranny for my 66 stang but I have no idea how to know if it's in good shape.
Some one clue me in on how to inspect a used tranny that is not in the car.

Thanks!!

 

[Mustang5L5]

A t-5?

Honestly, you need to open the top cover. That involves pulling the tailhousing off first.

Only thing you can do with the trans on the outside and check endplay. That's not the side to side wiggle of the input and output shaft. That's normal. Endplay is the in and out movement. If you grab the input and output shafts and try to pull and push them in together, they should not move, or move no more than 0.003".

That's about all you can check really without opening it up