Vibration - possible dmf?

[stewartbaldwin]

The car has recently started to vibrate under certain conditions and I wonder whether it is a symptom of the DMF. At a steady 2000rpm or thereabouts and when I pull a trailer, there is a distinct vibration from what appears to be the rear of the car. It is always there, but I can drive through it. I have had a poke about under the car and there are no obvious loose panels or play in prop shafts and drive shafts ( 4 wheel drive, remember!)

Any suggestions? Having followed various threads, there does not appear to be a single mass flywheel for my model, but I could easily be jumping to the wrong conclusion.

[booke23]

The car has recently started to vibrate under certain conditions and I wonder whether it is a symptom of the DMF. At a steady 2000rpm or thereabouts and when I pull a trailer, there is a distinct vibration from what appears to be the rear of the car. It is always there, but I can drive through it.

 

Not classic DMF symptoms at all. But I'm not sure what else to suggest. As Mike says an out of balance wheel? Having said that I did have a pothole damaged tyre that partially delaminated produce symptoms like this.  

[nickguzzi]

You could try a wheel swop.  If the effect changes ends, then you have at least narrowed it down.  A simple no cost test.

But as it seems engine speed related, rather than road speed, then I suspect the cause lies else where.  As you appreciate, these sorts of things are difficult to diagnose in the flesh, and via the www near impossible. 

I did solve a rear vibration problem on an Austin 1100 - yes that long ago - by finding a bit of coat hanger type wire trapped up in the rear wheel arch.  Nor offering that as a possible cause, but sometimes the most banal things can bring about the strangest sort of consequences.

Have you had any work done on the vehicle recently?  Some parts should be fitted in their working position.  Many suspension parts for example should be tightened with the car on its wheels.  If so that would be a starting point.

Bear in mind vibration can travel trough structures and manifest itself somewhat remotely from the actual cause.

If I had the car on a ramp in front of me, I would probably have a good look at the exhaust system first.  Hangers still ok? Loosen the clamps and joints, see if it preferres a slightly different alignment.  A good look at engine mountings too.  Or engine or battery cover?

Good luck.

[stewartbaldwin]

Thank you for the replies. I don't think it is a wheel balance problem as it is not road speed dependent - it will occur in the lower gears during acceleration and then disappear. Harder acceleration makes it worse. Sometimes there is a quite a loud booming echo around the cab that sounds like something vibrating at it's natural frequency. This is why I checked for loose sound proofing and heat dispersion panels under the car. I know the sound or vibration can carry, so it may be a problem at the front of the car, but I can't identify any loose panels. I have had no work done to the car recently. The only other clue may be that it started immediately after the car had not been used for five weeks. I know this is like looking for a needle in a haystack, but you never know whether somebody has come across this.

[Russler]

I have a similar issue to this and am almost certain it is a) wheel balancing or mis-shapen tire which I understand is common on the oct "sawtoothing"

 

I would check those areas first...like someone suggested swap wheels round...just to check

[rwbaldwin]

If you coast, is the noise still there?

[stewartbaldwin]

No, there is no noise on coasting and the tyres were only fitted earlier this year. I have not checked for sawtoothing yet