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[Jan Suhr]

I have a problem on my winter car. When turning under power it vibrates and sounds. Worst when starting from standing still and turning around a street corner. Most when turning right and there as well going left but not as much. It seems like it looks up briefly on and off

Brakes are OK

Doing a right turn on idle and not under power no noise or vibration it is only under load.

Nothing when going straight ahead.

So what could it be?

If it is the diff wouldn't give noise in all situations?

Could it be the driveshafts?

There is no common wheel bearing sound and driving at speed straight ahead it is quiet.


Appreciate any advise


Thank

[Doctor Gollum]

What condition are the tyres and road surface?

Does the TC light flash?

[Jan Suhr]

Tires are fresh and didn't make any sound on the car I had them on before.

No TC light

[Jan Suhr]

And the tires don't make any sound when driving straight on the road, eve up to 70mph speed

[Kevin Wood]

Does it have a limited slip diff? Just thinking that they are probably more common in your part of the world?

They tend to groan a bit when turning.

[Doctor Gollum]

Did you spin the wheels?

Switch the TC off/sports mode on and see if it repeats

[polilara]

Does it have a limited slip diff? Just thinking that they are probably more common in your part of the world?

They tend to groan a bit when turning.

I have (Finland) limited slip diff, it really make that sound as described by Jan Suhr.

[Jan Suhr]

Well it is not just a sound it is kind of heavy vibrations too. Turning on gravel the tire sort of drags and the release a short moment before dragging again.

I haven't checked yet but I believe cars sold in Sweden cam with the limited slip differential.

[Doctor Gollum]

It could also be the traction control doing its thing as that will brake the spinning wheel, usually the inside one as you turn

[Jan Suhr]

It could also be the traction control doing its thing as that will brake the spinning wheel, usually the inside one as you turn

I just came back from a little test run on a gravel road.

With TC turned off it spins both wheels, so we can say that it has a limited slip diff.

The situation with the vibration is the same with TC on or off.

What confuses me is that there is no vibration when the car just roll around a corner. It only vibrates under power.

It sounds like it could be the diff but wouldn't it also vibrates when no power is applied?

[MonzaGSE]

Have the exact same as you described om both my 86 Monza and the 95 Omega mv6. Typically when you accelerate from a standstill around a corner. I always thought it was the lsd working. Had both cars for years and they dont seem to get any worse.

[Andy H]

Have you checked the condition of the rubber bushes on the differential and the subframe?

Is it possible that you are getting metal to metal contact due to excessive movement in a worn rubber mount?

[Kevin Wood]

Might also be worth replacing the oil in the diff if it is a LSD.
Be sure to use a mineral oil with the GM LSD additive.

[Jan Suhr]

Might also be worth replacing the oil in the diff if it is a LSD.
Be sure to use a mineral oil with the GM LSD additive.

Yes I have been thinking about it and I'll do it soon.

[LC0112G]

Might also be worth replacing the oil in the diff if it is a LSD.
Be sure to use a mineral oil with the GM LSD additive.

^^^ This ^^^

And you MUST use the additive. The additive is a friction modifier which allows the diff plates to slide smoothly over each other. If you don't use the additive the plates release and grab suddenly, which isn't good for any of the LSD gubbins. It causes the plates to get very hot and wear rapidly, and ultimately this wrecks the LSD.