V6 Tdi Strange Vibration between 60 and 70 mph

[Pat J]

I recently bought a '99 V6 tdi estate and it has a strange vibration through the body between 60 and 70 mph.
I've had the original wheels rebalanced and the tracking and alignment checked. I have now tried a different set of wheels and tyres and the vibration is still there.
It doesn't feel as if it's coming through the steering wheel and has me baffled as to what it is.
Any help and advice appreciated.

 

[spartacus 68]

Is it a quattro? If it was, check out the central bearing carrier. The rear diff rarely fails, but seals can weap. Has rear diff gear oil been changed?

If it's not, then go back to the front suspension. It's a complicated set-up with upper and lower control arms, all of which can wear. Quick check is to raise the car and hold wheels at 10 to 2 position and try to move from side to side. It should be tight with no lateral movement. Other suspects could include the ARB bushes, ARB drop link or worn tie rod.

The rear of the car isn't as bad, but check it out. I'd even check you haven't broken a coil spring.

 

[Pat J]

It's a 2wd going to check rear bushes first as it feels as if it's from the back

 

[Pat J]

How hard is it to change the bushes on the rear beam as I'm looking at changing them for powerflex ones.
Can't feel any noticeable play on either of the front wheels.

 

[spartacus 68]

Check out this great thread from PAULF.
http://www.audi-sport.net/xf/thread...t-and-rear-suspension-parts-with-pics.159557/