Ok car is a 89 formula 305 700r4w/shift kit. This problem just happened about a week ago. At about 50+ the car gets a viberation coming from the middle of the car, Feels just like a u-joint going out so I replaced them, No change, well someone told me to check the tailshaft bushing it was worn alitte but just because it was wore I changed it anyway, NO CHANGE, . Now somemore info, if your going at 50 and put the tranny in Netural the vibe gets worse, put it in 3rd and it gets alittle better but not much, Someone also told me maybe the driveshaft is bent so I pulled it out and checked it with a LONG stright edge, no bending at all, no weights are missing that I can tell. Also tried running the car on the lift and vibe is still there, so I know it has to be in the drive train somewhere, Can anyone give me some advise to try?

P.S. Tranny was rebuilt about a year ago.

Oh yeah also checked to make sure the engine and tranny were tight and they are same goes for the converter to the flywheel.

 

Just because the weights seem to be there does not mean it is balanced well. CHeck your trans mount too, but it kinda sounds like the drive shaft is out of balance...How many miles on the car???? It may even be the tires, maybe out of balance or a broken belt even. HTH

Keiran

 

car has about 160,000 on it, I will get the driveshaft balanced and see what happens if anyone else can help me please let me know.

 

I thought that if a moving car vibrates when in neutral then you can rule out the transmission and driveshaft.

 

Well for the most part yes...but if the car is moving...the driveshaft is moving...I would probably check my tires first before yanking out the driveshaft...Get the tires balanced at you local auto shop..This is cheaper to try first..ask them to check the tires out for broken belts too. go to a shop that won't rip you off though...If this doesn't help, then I would try the shaft.

 

Well I finally figured out what is causing my vibe, I have a bent output shaft AGAIN, no the car has NEVER been netural droped, I know this because I am the only one that drives this car, but my question is how and why are these shafts bending? I have the factory driveshaft in it and I checked the length of it and it is ok. Can anyone give me any ideas. BTW I will post pics of it just as soon as the builder gets done with it.