Possible bent axle.
 

1983 rx7 gsl limited slip disc. I noticed the car would start shaking at 30mph and got worse as speed increased, also the wheel would hop when coming accelerating into first. It would have a sqeak as the tire turned in the same spot. I put new shocks and brakes. The sqeak and vibration was still there so I had tires balanced, no difference. I put the car on jack stands and had somone watch the rear wheels as I accelerated. He put his hands on the parking brake cable and the sqeaking stopped when pushed.. So I disconnected the driveshaft and ran through the motions. No vibration in clutch or transmission. Reconnected and I watched the tires spin the time. The right tire was fine but the left tire was warbling horribly, caliper and all. So I went ahead and ripped apart the rear end, I notice that the differential only turns in one direction, is this right? And could a bear bearing cause a wabble that bad? I'm looking at replacing the Axle , should I go ahead and replace the third member? Finnaly got car running and I get to this -_- -nick-

the squeak is the classic bent axle symptom, you should just start with the axle, its actually pretty easy

I've got a really good member on here thats going to ship me some axles.

Is there a good place to find the bearings? It needs a new crush bearing :(