ryle

iTrader: (19)

I've been noticing a strange vibration when I am decelerating from about 60mph or higher. I decided to experiment a little bit to see if I could narrow down the problem but this one has got me stumped.

I drove the car out on to the highway so I could get up to speed. Took it up to about 70 and then let off the accelerator. The second I let off I get a nasty little vibration that feels like it is coming from directly below me. I then put the car into neutral and the vibration got worse.

The trans is a RPM level 5 4l65E that I bought from a user on here. I am using poly trans an motor mounts. Torque converter is a Midwest 3600 lockup converter. Driveshaft is stock LS1 and the Rear end is a stock 3.42 ten bolt.

Anyone have any ideas on where to start looking? I don't want to think it's the trans, but I guess it could be. I just noticed this vibration today and can't remember it ever being this bad before.

Thanx in advance!

texas99Z28

funny thing, after a local shop removed, had my tranny rebuilt, and re-installed it, I have a vibration on de-cellerating from around 45mph. Took it back to them, they are claiming a rear wheel is causing it. well, just had new tires put on, and wheels balanced. Please let me know if you hear anything from this thread, as I will you. Curious!!!!!!

Orange Juice

iTrader: (3)

Try putting your car up on a drive on hoist and checking the angle of the tail shaft to the angle of the drive shaft. I had the same problem and played around with the shim at the top of the trans mount. I ended up taking the shim out of the car and having some thinner ones cut at a lazer cutting shop. Then played around with the settup.

ryle

iTrader: (19)

Didn't think to look at that. Mine doesn't have a shim whatsoever so ii'll look into it. But would it only vibrate on deceleration?