I have a vibration when my car is in gear on the freeway, the vibration only when u jump on it or u put the car into 3rd gear, it is only in the high rpm's, what the heck could it be. The transmission is a 700r4 auto. I have new U joints and the rearend is ok, it is coming from the transmission area. PLEASE HELP ME!!!!!!!!!!!

 

Driveshaft may be out of balance. That's a fairly common problem with the steel shafts in these cars.

 

hehehe you said shaft

 

I would check to make sure the u-joint at the rear of the drive line is seated all the way into the cups of the rear yoke going into the rear end. Did you make any mods to the car and then the vibe started. It can also be caused buy the slip yoke giong into the tranny if it is worn out and sloppy. One easy way to check is to put the rear of the car up on jack stands and have a friend bring the speed up to the point you have been experiencing your vib and look at the drive line and wheels to see if anything looks out of wack.


support our troops

 

Check out your transmission mount. Common problem.

 

Torque converter bolts....happened to me twice... it will make a HELL of a NOISE though

 

S.Holly good sugestion. I did not remember that but My dad had a problem with the converte bolts about 10 years ago on a one ton 454 chevy pick up and he said at the time it would shake like hell at anything over 50 mph

 

I would not waste my time on the convertor bolts Unless they were removed & replaced recently.

 

The trans mount is new and the gears and rear end were just checked recently, the reason for this is because the #7 crank bearing spun and i had to rip the motor out and rebuild it, the u joints on the car are new and really good, and the trans mount is polyurethane, i know that those are in there all the way because my mechanic did those, but the car was vibrating before i even had those replaced. I think that it really is going to be the driveshaft, I'm going to replace that with an aluminum one and go from there if it doesn't stop after that is done. I really appreciate the input and hopefully it works out for the best. Thanks for everything!

 

you can also get you drive shafted balanced at a shop... much cheaper....

I need mine done..

 

take your drive shaft off and turn if 180* and then put it back on see if that helps!

 

also make sure that youro crossmember is tight!

 

There is one other thing that you might look at if you have put the car up on stands and ran it as I described earlier and found nothing wrong with the drive line or rear end. I know of a thrid gen that had been over reved to many rpm,s and it balloned the torque converter. .Your flex plate is also balanced and its not out of the question that a balance weight could come of and cause your problem

 

Something else for you to check. My 91 RS had a vibration at times at freeway speeds that I thought was an out of balance driveshaft. Turned out that after years of hard launches, the bolt holes in the torque arm, where it mounts to the rear end had elongated. This let the rear end housing roll slighty back and caused the pinion to angle upwards slightly more than it should. I installed an aftermarket torque arm, which pulled the pinion angle back down where it's supposed to be and the vibration is gone. I guess you could also weld some washers over the holes or weld on a couple pieces of scrap steel, then redrill the holes in the right place, if you don't want to spring for the aftermarket torque arm.

 

My A4 vibrates quite a bit too. That was noticable after I changed the torque arm mount and the tranny mount to poly mounts. could be that they are transmitting the NHV over to your car body.