HOW BAD IS IT!

I just bought a 73 Challenger with a 4 spd. When test drove it the trans made all kinds of racket, but it seems to go in gear ok and the noise went away when I put t he the clutch in so I assumed it probably had a bad bearing. I towed it home and and I would only move in and out of the garage to work on it. Today I drove it out and I couldn't find neutral and the car wouldn't move without burn up the clutch and making all kinds of popping noises. I put the car up on jack stands (wish I had a lift :() to take a look. I pulled the inspection cover and everything with the clutch looked fine all the shift linkage looked fine and the rear end turned freely. I started the car up (while on the stands) and put into gear to see if the tires would spin. Again I could never find neutral and the rear tires would spin erratically. All while making all kinds of noises! THIS IS NOT GOOD! :BangHead:

I have an A-body transmission that I can use for parts but it may be an Overdrive. Can anyone tell by looking at the gears? The case is aluminum but the tail shaft is cast iron and the side cover is and old style with the brass slider forks so I don't know what it is?

Here's a picture of the gear set toward the front is on the bottom
View attachment 1715033398
I would remove all 3 linkage rods and set 3 levers at neutral position. Star the engine, while on jack stand, see if wheel spin; if it does apply brake see if it stop