Vibration under acceleration , any ideas?

[jl34]

Hi all.

My GTO 3R is starting to suffer a bit of vibration when accelerating hard toward the top end of the rev range (4K upward). The vibration dissappears when the car is backed off and coasted on the throttle so i dont think it is tracking or wheel balance or the usual suspension wear (although i could be wrong).

The vibration feels like it is running through the car, maybe with a rear bias but difficult to tell. Anyone any ideas what it might be ?, the car has only done 23K miles and does a couple of trackdays a year but generally isnt over used. Tyres are new. I was wondering about worn engine mountings being a possibility, anybody got any thoughts on that ?

[mgbond]

Have u checked hub nuts arnt loose?

[GTO600]

Driveshaft,
Jack the car up on each side & check for slop in the outer joint by rotation the wheel back & forward, if so you should easily be able to see the offending one.

[jl34]

no i havent , will give them a good check over, although im guessing they would vibrate all the time and not just acceleration ?, however good shout will have a check

[jl34]

GTO600 said:

Driveshaft,
Jack the car up on each side & check for slop in the outer joint by rotation the wheel back & forward, if so you should easily be able to see the offending one.

yes outer driveshaft joint, another good idea!

[mgbond]

Maybe it's the dreaded cracked aluminium block that holds the ball joint. Not sure what symptoms that would give.

[V1DL3R]

Check the exhaust bracket isn't snapped on one side the resonance under acceleration can cause it to shake or could be the drive shaft bearing.

[funkybmx1]

They don't the drive shafts. Mine I could notice from about 4th gear 100mph on would under hard acceleration it would vibrate. And stop the moment I lifted off

[jl34]

[quote=funkybmx1]They don't the drive shafts.

Sorry can you explain this ?

[funkybmx1]

Sorry. You said your would think they would vibrate all the time. They don't. Mine only started vibrating from about 4 gear 100 mph onwards. But stop the moment I lifted off. To stop I widened the whole rear end. But I got the rose jointed bottom wish bones and shined the top of the upright out

[andygtt]

when my inner CV went on my drive shalf it vibrated terribly above 100mph only under acceleration... it went when you lifted off or accelerated slowly

to be fair mine was a horrific vibration, but the joint was totally destroyed.