speed_demon24

iTrader: (6)

Ditch the poly trans mount. Putting in a rubber LS1 trans mount cured my vibration that I was chasing for years. One of the best de-mods I've done to date.

JwMonE99

iTrader: (1)

Its probably the 5th and 6th gear in the transmission

unioncarpenter84

iTrader: (22)

i have the same issue with a 94z28 with a a4 tranny never did figured it out

chris_14kingz28

here is a quick video of it goin from 60 to 75 in 6th slow acceleration windows are cracked like half and inch but thats what it sounds like.

draggin97s10

iTrader: (2)

I vote the output shaft bearing, I would have the transmission gone through...

ps my car has a similar problem...and its note driveshaft, wheels or any of the things already mentioned

chris_14kingz28

I just took the car to get the tranny completely goin through and built so Mabey in a few weeks I will find out if it fixes the problem

draggin97s10

iTrader: (2)

thumbs up! i have a sneaking suspicion that it will fix your problem

Turnin20s

iTrader: (12)

I have the same issue with my car. It got worse after the rear end swap, probably from all of the solid joints. I have a Strange chromoly driveshaft so I'm sure thats not the problem and I have changed the trans mount with no change. I'm pretty sure that the trans is my problem.

Post back up when you get the trans back....I'll be subbing for the results

chris_14kingz28

Thanks a lot for you guys help I will let y'all know how the new Trans goes

chris_14kingz28

Just had a call from the guy who built my t56 he said the vibration is still there and he said he replaced everything that he could. I'm stumped i don't know what to do next that might bring me to this problem

nascarnate326

iTrader: (1)

could the "backlash"(i think thats the word) of the gears be doing it? As in there is too much slop or play?

chris_14kingz28

No everything is tight with the rear end 5 month old moser 12 bolt .

draggin97s10

iTrader: (2)

the balance of the tires could be good..but is a wheel wobbling??? I'd check the straightness of all the wheels

chris_14kingz28

I've ruled the wheels and tires out I have jacked up the back of the car and I have removed the wheels and brakes and with the wheels and brakes off the car it still vibrates at 70 every time.. I'm starting to think it might be my poly Trans mount ??

cprmn14

Have you checked your steering components for play? When my endlink broke it vibrated terribly when stopping. Maybe something similar going on, but it sounds like something with the drivetrain is severly out of balance. Weird that it does it in neutral aswell. have you checked your flywheel?

chris_14kingz28

Yes the car has a new flywheel

Turnin20s

iTrader: (12)

That sucks man. Try a rubber trans mount maybe it will help

chris_14kingz28

Yeah I'm gonna try it

Fazz73jr

iTrader: (3)

Are you sure your new flywheel is NOT a neutral balance flywheel? The stock lt1 is external balanced and requires a weight on the flywheel/flexplate. Ive seen aftermarket flywheels without this weight on them for guys like me with an internal balance 383.