So before I go ahead and purchase a new drive shaft I wanted to see what you guys had to say. The car vibrates around 60-70 real bad. It also vibrates really bad if you take off fast and get your rpm's up to around 5000. I balanced the tires so that rules them out. My steering wheel has no vibrations, the vibrations themself seem to be coming from right under the shifter...where the first U-joint is. It is not the motor mounts. Is there any other possible reasons for the vibrations?

 

Tell us more about your setup. Is this an n/a or turbo? Do you have a loud exhaust which resonates (causing vibration) in the cabin? I have some vibration in my GTU but it's just due to resonance. I checked the u-joints.

Pull the driveshaft and check for play in the u-joints before you go and spend money on a driveshaft. Pull the exhaust off and the driveshaft is held to the rear diff by four bolts.

 

That sure does sound like driveshaft failure, just make sure you fix it before it breaks, mine broke while i was driving, and locked up my tranny. I didnt have reverse for a good 6 months =(...

 

Fix'em

http://www.rotorwiki.com/index.php/R..._FC_Driveshaft

 

Yea my bad, I have a 1986 rx7 n/t. My exaust is pretty tame, I dont think that is the reason. The stock driveshaft doesnt have replaceable U-joints so I can replace them. Im pretty sure its the drive shaft, I just didnt know if it could be something else because this car is new to me.

 

Most likely is...it is pretty easy to remove and if you have a drive shaft rebuilder in your area take it to them and they will test it....usually a charge $25 or so...ask. What I did was have my local rebuilder-machine shop to rebuild mine and put in replaceable and greasable U-Joints. I did not save any money, but next time around I will.

 

Read the freaking howto. You CAN replace the "non replaceable" u-joints.