I am thinking something to do with the tranny but you guys may know something I’m missing.

OK, the other day I start my car after it was sitting for a few hours and hit the main road and start accelerating I begin to feel a BAD vibration that seems to increase with MPH not RPM so I first think a tire is out of balance. I get to the light (very long light) and leave the light with no vibration at all. I did more stop and go driving but no vibration so I decided to dismiss it as something F^^ked up must have happened and all is well. Tonight after visiting my gf I leave her apartment hit the main road an accelerate there is the BAD vibration again but it feels a little worse but maybe that was because I accelerated faster and to a higher speed. I even let off the gas to verify that it wasn't an RPM based vibration but was speed related. So, I come to a light and sit for almost a minute then go again and no vibration, not for the rest of the trip home The only thing I can think of is something to do with the tranny and after it warms up a little it goes away.

What do you guys think?

 

driveshaft

 

Good thought trey.

 

i'm having the same problem....when i hit about 65+ it starts, and it increasingly gets worse...

it's not a random vibration, it's kindda timed...it's happens in ~2 second intervals....

 

How does this explain that it only does it when cold and after that nothing at all? I drove the past couple of days at well over 70MPH and no vibe that’s why I thought that it wasn't the driveshaft. I know what the driveshaft feel like and it was similar but it went away within 5 mins of starting the car. And, after i seem to stop for a little while (at a light or something)

 

Iv got the same problem with my car and it turned out t be the driveshaft, so I got a used LS1 drveshaft and it works great.

 

have you checked all your mounts, motor, tranny and the such?

it could be the driveshaft i suppose.

 

the vibration used to be worse, but my friend put in some kind of mount to decrease the vibes...i'll ask him exactly what it was and get back to ya.

 

I drove the car all over the place today without a single vibe. I even tried to let it sit for a few hours between driving and nothing

 

You might want your tires/rims checked to make sure that they are balanced.

I recently bought a used car (front wheel drive) and i would get a vibration at 70mph. I didn't think too much of it then the other day my front tire self destructed broke the bead....a guy that i had passed on the freeway stopped and told me that when i went by he could see the wheel was hopping while i was going down the road.

I noticed that the lip of the rim was bent a little when i took it to get a new tire put on the tire guy placed the weight right on the bent part. Vibration went away. Just something else to look at.

 

well, found the problem....once we took out the old tranny, we put in a caprice tranny, which had a different tranny mount...and that was causing something to hit the floor.

 

THUNDER CATS HOOOOOOOOOOOOOO!

 

trey, come on! if ur gonna do it, then ya gotta do it right!!!

thunder! Thunder! THUNDER CATS! HOOOOOO!!!