The car drives fine until you get up to 25 MPH, then I car hear a thumping noise, and the steering wheel shakes, Other then that it shifts fine and everything works like it should.
The car was wrecked by the prevrous owner, and the pass side wheel was pushed all the way back, but all of that was replaced before I got it. I was topd that the noise was a bad axle (which was bad). After I replaced the axle the vibrasion reduced, but the thumping is still there.

 

I don't think the problem come from your tranny.

Wheel bearing?

 

It is probably an issue with the length of the axle.

 

What axle are you using?

 

the driver side I got of raxle.com the pass side I don't know. It has red cc boots
How do quick check if my wheel bearings are good

 

Chek on what speed your going when it's shaking.

Jack the car, and see if the wheel is moving like if the bolts were not tighten.

EDIT: Maybe it come from your direction, and with this tips, you'll know whats going on with your problem.

 

I checked the wheels, they are pretty firm, the vibration starts at about 25 mph

 

sound like the axles are binding up you might have get the fram pulled ill let the body shop check the fram

this may sound stupid but it works you can jack both side of the car up start it up put it in 3rd gear and hold one wheel with your hand and give it alittle gas and see what wheel it coming from

and another thing is your rack might be bad to

 

could be front end like ball joint or tie rod

 

i jacked the car up put it in 5th, and the noise was comming grom the transmission, both wheels were not making any noise.