Hi All,

Car: 2006, 2.5 V6, HSE

Just recently after putting my summer wheels back on, and about 2 weeks had passed. the car decided it was going to shake itself to bits. i pulled over and checked the wheel nuts, all where Ok. i went on my way with no issues, or shaking for the rest of the journey(100km). again it is starting, normally it comes and goes a small amount, through the car, then it gets bigger(speed varies), until I stop. when I pull off again it is either gone completely or quite small.

The shaking doesn't seem to originate through the steering wheel, and once started, doesn't seem speed related. Sometimes I think it is worse after going around a left bend.

If you have any ideas it would be great. Cheers
 
Worn joints in the transmission can cause that - you get a drive shaft or part of the propshaft going off centre.


Is it engine related? Dip the clutch and drop the revs at speed..?

Is it speed related - most transmission vibrations will be.
 
Worn joints in the transmission can cause that - you get a drive shaft or part of the propshaft going off centre.


Is it engine related? Dip the clutch and drop the revs at speed..?

Is it speed related - most transmission vibrations will be.

No clutch, the V6 is only available in an auto ;)

Drive shafts can cause heavy vibration, although it's normally constant and speed related.
Well worth checking the fluid level indicator the gearbox too.
 
I'd check your tyres are all still at the right/same pressures - I presume they are all the same make/model.
 
Thanks for the ideas.

On way home I did some experimentation after it started.

It is normally worse after a right hand bend/corner and accelerating out, above 1500rpm.
when in a straight line and above 1700rpm, if i completely let off the accelerator, then it stops almost instantly, when i accelerate again, it comes back.
if i back off and go straight back on, it is much worse immediately.
I am thinking one of the drive shafts is pretty worn, hopefully i can get it in the air over the weekend.

cheers
 
Check the inboard CV joints for wear. And see if the large bush in the lower engine tie bar is sloppy. ;)
 
sounding more and more like drive shaft coupling ..from memory of they are gone enough to do this, the play will be bloody obvious with a hefty wiggle...
 
If it only started after putting the wheels back on you may have a loose balancing weight or have lost a weight.

+1 on getting the wheels balanced.
 
unbalanced wheels will usually have a small range. see if it happens from Xmph to Xmph only
 
So managed to get it in the air, didnt manage to balance wheels, did wiggle everything, all seems solid enough, managed to tighten the nut in the front drive shafts, a small bit.

did notice that the propshaft could be pushed up enough to touch the vehicle, around the VCU, so maybe slightly related to the bushings/Bearings there.

Also looking for new tyres as they are quite old, worn enough to go for full set, although front ones look slightly newer than the rear.

Cheers
 
did notice that the propshaft could be pushed up enough to touch the vehicle, around the VCU, so maybe slightly related to the bushings/Bearings there.

That's a very common fault and one that needs fixing anyway. Normally the bearing vibration mounts are stiff enough to contain the VCU

That needs fixing anyway - its not hard to drop the whole shaft and disconnect the VCU and carve the old bearings off with a grinder and fit new ones.


Make sure they are lined up straight though

You may find they are run out anyway and that is also the cause of the vibration.

The good news is the car is serviceable without the prop-shaft while you get it sorted
 
front ones look slightly newer than the rear.

By that I suppose you mean more tread - so bigger - so should go on the back.

Most of what you have said indicates wind-up to me - eg it starts when cornering, not speed related, stops when you leave the car for a bit (ie pressure released within VCU). Some bits don't.

I'm guessing it is related to your prop shaft joints, VCU carier bearings or the rear diff mount bushes being worn and wind up (due to poor tyres) is contibuting to it.
 
had the prop shaft off last summer, with no problems, so will take it off again and see how it runs, and replace the bearings/bushings. Also will put the bigger wheels to the back, whilst in the air.

cheers
 
SO, I have removed the propshaft, and the effects are much reduced, now the vibration does occur, but has more of a pattern to it, higher rpm and lower speeds and after about 50mph, it is virtually gone, on the highway it is fine.
so beginning to suspect the tyres condition, and will look at the mounts.
 
Its one of three things :
rear diff mountings one or both,
Lower ball joints on the control arms (usually opposite side to steering wheel)
And definitely wheel balancing
 
I have ordered the Tie rod mount after looking through some more threads, and new VCU support bearings. I will try the tie rod mount first, then I will go for tyres, I want to do it in steps , to see if I can actually find one cause, of course it might be a collection of items, we will see.
 
So to all, I have replaced the tie rod, and it appeared improved, but now it has more of a pattern when it happens.

Currently when it happens , it is more lumpy than vibration.

It is definitely worse when adding power on small to large inclines, releasing the pedal removed the problem, but of course I don't go up the hill.

Currently there is no prop shaft installed, and the problem is still present.

Still haven't swapped or balanced the tyres, but the winter ones go on soon, and they are 4 new ones.

VCU bearings replaced, just waiting to install unit again.
 

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