I recently put in my new rebuilt tranny. I bought the car apart so i dont know how it acted before. Anyway when ever I floor it and it gets in the high rpms the shifter starts to violently shake. The wheels also lose traction around that point but i dont really think its wheel hop. What could be wrong???? Oh and I changed the tranny mount.

 

Since no one has jumped in here I'll see what I can come up with. I take it from what you have said that it does not vibrate when in neutral and motor reved up.

I assume that this is a 4 speed.

Does it do this in every gear?

You said the car was in parts when you bought it, so:
Have you had the drive line checked for balance?
Check yoke on both ends of drive line carefully
Check yoke and shaft on dif, is something bent.
With the drivel line disconnected from diff, and rear raised does the rear end
rotate smoothly?

Well these are things I would check, maybe some one else will have some ideas.

 

does it vibrate at certain speeds or is it load (rpm) sensitive?

-start by checking motor and trans mounts and then look elsewhere.
- check u-joints
-look for loose bolts (mounts, bellhousing, etc)
- an unbalanced driveshaft will tend to have vibration based more on vehicle speed instead of load
-some torque converters are balanced... they have weights on them and they are supposed to be reinstalled in the same position. Same goes for flywheels/ flexpates