Transmission issues.....

[Bryc18]

Alright, so I have this 62 bird sitting here. Original trans in it was cracked inside. Decided to get one from someone else who said it was sitting on a shelf for three years. Didn't take it apart or anything. I installed a new vacuum diagram on the rear and checked vacuum and at idle seems good there. Problem is, it will do nothing when selecting reverse or drive. Now if I increase the rpms to wide open throttle, then the transmission will engage and spin the tires but, once I let off the throttle, it does nothing again. Kind of at a loss as to what is going on with it. Fluid level is good, the linkage is adjusted right. Not sure about line pressure or what it should even be either