ckyconan2003

iTrader: (2)

well, my dad told me about a vivbration he was having when he was doing over 90. so on my way back to college last night i decided to try it out. If im accelarating there's no vibration but when i let off the gas things start to vibrate bad, i feel like its coming through the transmission. Any ideas? 97 30th SS is the car.

WhyHelloOfficer

iTrader: (5)

Have you replaced the transmission mount at all?

If you have the energy suspension poly-mount, you might want to double-check that you didn't put the spacer in. If you did, take it out and it should get rid of the vibration.

If you have the stock mount, it might be on its way out. Get under the car and double check it.

ckyconan2003

iTrader: (2)

aight, i'll have to check that out.

WhyHelloOfficer

iTrader: (5)

It could also be something as simple as the tires being out of balance. If you haven't had them rotated or balanced in a while -- it probably wouldn't be a bad idea to spend the $25-$30 to get it done at a local shop.

ckyconan2003

iTrader: (2)

balanced tires for 200mph and a blanced riveshaft. all that has been checked already according to my dad.

letsrun97z

iTrader: (7)

where do you get them riveshafts? lol when mine was doing that awile back the stickie weights fell off

94 F-body

iTrader: (1)

I would look to see if you thew a weight off of the drive shaft or tire, but if your rotors are warped then you will need to turn or replace them

Trivaldi333

I had the same problem to, i took my car down to a speed shop, they tested it and said it was the driveshaft. They recommended buying a new driveshaft, so i did. I ended up buying a carbon fiber driveshaft from precision technologies. If i can remember right i think it was called the critical link. Eversince installing that on my car the vibration went away. and ended up saving a few pounds by switching from steel to carbon fiber. Hope this helps!!!

donkey mule

Youch! A carbon fiber driveshaft is expensive!

ZFan88

iTrader: (4)

Sounds like the driveshaft. Balancing it doesn't always work. Just go to a junkyard and pull a later year LS1 style out and direct swap them. Or a 1LE 3rd gen will work

RedRyder518

iTrader: (2)

Try this...if you have had a gear change, try swapping the driveshaft 180 degrees at the rear yoke. I had a gear change and had the EXACT problem...I would vibrate at about 85+ MPH, but once I rotated the driveshaft 180 degrees in the rear yoke, problem solved!!

mhayes2344

iTrader: (3)

I bought my car (96 WS6) with 373's installed by a back-yard mechanic (wines a bit). It also vibrates a bit at higher speeds, so I bought and energy suspenion trans mount and what I thought was a ls1 aluminum DS (ebay seller lied about what the DS doesn't fit and I wasn't able to use it. I read a lot of threads about how the stock steel DS would vibrate quite a bit at higher speeds so I thought the new trans mount and aluminum DS would fix the problem. All I can say is the energy suspension mount only magnified the problem and when I go back from college for christmast break I'm going to install a new stock trans mount. My suggestion is to replace the trans mount with the OEM part and and buy an aluminum DS from a LS1 f-body....that should fix the vibration problems you're having.

jasonp31

I second the yoke idea, of switching it 180 degrees. Excellent idea with your symptoms. (assuming you've checked simple things FULLY, like tire/wheel balance, and rotors)

TransAmMan93

I had the same problem like yours, vibration only when not under power, it was my wheels cause the weights flew off on my left rear tire. i got it balanced and everything was fine