lt941

Hey everyone I'm having a bad vibration at 75mph. Tires are all balanced good, u joints are good. If I put the clutch in and put it in neutral the vibration stops and everything is smooth. Doesn't seem to matter which gear. Could this be the result of a bad tailshaft bushing or something worse?

myltwon

iTrader: (1)

Any aftermarket suspension? Stock gears? Stock driveshaft?

lt941

Stock everything except rims.

kinglt-1

iTrader: (26)

drive shaft.

lt941

Wouldn't it vibrate even if it was in neutral if it was the driveshaft?

kinglt-1

iTrader: (26)

Ahh yes I read your post wrong. I thought you said it still vibrates even with it in neutral.

hrcslam

Does it vibrate with the clutch engaged in nuetral?

98CayenneT/A

X2, get it balanced and new joints

lt941

It doesn't do it nearly as bad. In neutral without the clutch engaged its smooth.

SS RRR

iTrader: (2)

Smooth with no load on driveline usually points to backlash adjustment on the gears is not right.

98CayenneT/A

I had a clunk when I would shift into 3rd, sometimes a shutter, and a vibration in 4th (od, I'm a A4 ) on the highway. Checked my u joints they seemed fine, after a few trips to the track it got worse so I yanked the driveshaft out and had it balanced and new joints pressed in anyways. Every issue is gone, I think the driveshaft is something to look into

hokeplaya05

iTrader: (3)

i have the same issue, vibrates at highway speeds in 6th gear. i have an ls1 alumunum ds in my car that i got used, luckily i kept the stock steel one and am going to swap it back out and see if it goes away.

lt941

How much would you want for the aluminum one if you wanted to sell it?

lt941

How do you adjust the backlash?

hokeplaya05

iTrader: (3)

not looking to sell it, sorry. just using it to see if the vibration goes away, then i know if i need to balance the aluminum one or get new u-joints. i know the steel one is good, so just using it to help diagnose the issue

lt941

When I turn sharp and am just idling in 1st i can feel and hear a clunking sound through the shifter. I'm not sure if that would be related or part of the problem.

98CayenneT/A

Is it like a snapping and goes away when you get straight?

lt941

Its more of clunk. Yes goes away when straight

98CayenneT/A

Just a guess but it may be your rear end. Auburn diff.?
I would get the back end up, pull the cover off and check the spider gears and ring and pinion. If all looks good fill it back up and add two bottles of limited slip additive

lt941

Could that also be what's causing the vibration?