Techy help required please. (Non Zed related)

[EnthuZiaZT]

Could be a bent drive shaft Dave, probably on the back wheels. Check by jacking the rear up, put axle stands underneath to support it, crawl underneath so you can see the drive shafts either side of the diff, then get Jue to rotate the wheel. If the driveshaft is bent you should see it.

Mike

 

[t-tony]

Can you replicate this vibration with just the engine running or only when moving? The Touaregs have this when the centre prop. shaft joint fails and the only remedy is a replacement prop. shaft. If it was the DMF you would get it with just engine running. Is this a new thing or been there since you got it?

Tony.

 

[Grumps]

The Dual mass is mentioned as a possible issue the main thing mentioned appears to be the u joints
They all mention the issue between the rpm's you quote some have replaced the full transmission through warrenty and its still there as common as it is Even Kia don't seem to pin point it.

Bloody hell! When I was looking at 4x4 I wanted a touraeg. Couldn't afford one and these got a cracking right up online so went for one of these. Within a week it started vibrating. It's looking like trying to narrow something down around the prop area then. UJ's, prop itself or carriage bearing. Thanks Ant

 

[Grumps]

check the prop joints, had same problem on an old landrover

Thanks Pete. General feeling seems to be around that area.

 

[Grumps]

Can you replicate this vibration with just the engine running or only when moving? The Touaregs have this when the centre prop. shaft joint fails and the only remedy is a replacement prop. shaft. If it was the DMF you would get it with just engine running. Is this a new thing or been there since you got it?

Tony.

Don't know about when stood revving it Tony. I'll try it this morning. It started doing it soon after we got it.

 

[Grumps]

OK I've been out this morning and tried a few things to help with the diagnosis.

It doesn't vibrate if you are stationary and rev the car.

If you accelerate gentally right upto 5000 rpm it doesn't vibrate.

If you accelerate a bit harder it will vibrate between 1800-2200 in any gear.

If the car is vibrating and you dip the clutch the vibration stops.

I have a headache!!

 

[Antm72]

That seems to point to drive drain then. Rules out engine which is good.
Dipping the clutch takes the drive load off so it points back to the drive shaft and joints.
Think Tony has said it rules out your DMF as its not there when reving from stationary as its still spinning just not engaged.
It might be wear that you may not see but getting underneath after securing it on jack stands might help you trace it .

 

[Grumps]

That seems to point to drive drain then. Rules out engine which is good.
Dipping the clutch takes the drive me load off so it points back to the drive shaft and joints.
Think Tony has said it rules out your DMF as its not there when reving from stationary as its still spinning just not engaged.
It might be wear that you may not see but getting underneath after securing it on jack stands might help you trace it .

OK mate that's interesting. I hope your right. I was concerned when peeps were coming up with the dual mass flywheel. I will have a grovel around and see if I can find anything with play in it.

 

[Lee]

Agree with @Antm72 and with Tony ruling out the fly,and backed up with your test. Looks likely a shaft or prop.

 

[t-tony]

My money is on the prop shaft. I found I similar problem on one of the outside tyre fitter's 4wd pick-up, as some one had refitted the prop shaft with the centre bearing upside down and the shaft was running out of true.

Tony.

 

[Grumps]

OK thanks to all. We shall start there then. Fingers crossed.

 

[Tfp]

I concur, propshaft or driveshaft.

I had a Mk1 Mr2 with Exactly that fault, was the driveshaft.

 

[mwpe]

If the vibration is directly related to engine speed then I would not expect it to be propshaft or driveshaft related as these are running at different speeds depending which gear it is in. It is more likely to be clutch or gearbox related. The only things rotating at the same speed as the engine are the clutch and gearbox input.

 

[Redline]

I too thought it has to be before the prop-shaft. If it's rev related rather than speed related it's likely to be in or before the gearbox. Everything after that is proportional to road speed.

Does it appear only under load or does it disappear on no throttle?
Is it the same at the same revs in every gear?
Do you hear it if you knock it out of gear and coast?
What happens if you drop the clutch when it happens? (Btw - all diagnostic tests at the owners risk - just in case the gearbox explodes )

Just trying to narrow down which mechanical bits might be in use when it happens.

 

[Antm72]

I think Dave advised its not there stationary at any revs only moving under heavy load as under minimal load its not as apparent so drive shaft is still a good possibility.

 

[Grumps]

I too thought it has to be before the prop-shaft. If it's rev related rather than speed related it's likely to be in or before the gearbox. Everything after that is proportional to road speed.

Does it appear only under load or does it disappear on no throttle?
Is it the same at the same revs in every gear?
Do you hear it if you knock it out of gear and coast?
What happens if you drop the clutch when it happens? (Btw - all diagnostic tests at the owners risk - just in case the gearbox explodes )

Just trying to narrow down which mechanical bits might be in use when it happens.

Yeah as Ant says Ian. Sane revs in each gear under load only. No knocking at all. Runs smoothly apart from whatever this issue may be.

 

[t-tony]

Get the centre prop bearing checked Dave, and that its fitted correctly.

Tony.

 

[Redline]

I think Dave advised its not there stationary at any revs only moving under heavy load as under minimal load its not as apparent so drive shaft is still a good possibility.

I was hoping then that the frequency and was proportional to speed and extent proportional to load (throttle). My thought would be a joint in the prop shaft was damaged or the prop shaft or one of the drive shafts bent. My bet is a prop shaft joint or it's been dropped onto something and bent or damaged it so its unbalanced. I'd expect little vibration below 15-20 mph but more or less a constant amplitude but frequency relative to road speed above that unless you go through a resonant frequency when it would become undriveable. If it were the dual mass at some point it would likely ride through any vibration and smooth out.
I think @t-tony suggested jacking up one of the wheels and get someone to turn it while watching the rotating bits

 

[Grumps]

I understood some of that @Redline!!! In short were hoping something to do with the prop shaft or area of is bent or damaged in some way. I will jack it up and get my neighbour to have a look for me.

 

[Jack Ratt]

It's probably something simple Dave. Back when I were a lad and learning a bit of car mechanics from my uncles it was drilled into me to refit parts exactly the way they were removed.

Example, if you remove the drive shafts / prop shaft to attend to a clutch or gearbox job or whatever, then I was told to mark the parts so that they went back in exactly the right place.

May be your car has had a bit of work done to it prior to you buying it and just may be the mechanic hasn't followed this rule ? A misaligned prop shaft could induce excessive vibration, however if the problem has only just arisen the chances are it's a worn bearing of some description and as @t-tony has already suggested the prop shaft bearing is a good bet.