Rumbling vibration mystery

RealBeale · Dec 22, 2016

Hi.
I've had a rumbling noise and vibration for the last few months that I cannot get to the bottom of. It felt like a drive shaft failure so I replaced what I thought was the offending shaft to no avail. Anyway I've now changed all 4 drive shafts, the gearbox and swapped over the transfer box with a known good one , all to no avail. The symptoms give the exact same feel as a driveshaft failure. The prop has been checked and is fine but we fitted another to eliminate that too.. Cannot think of what else it might be.

Tony Reeves · Dec 22, 2016

RealBeale said:
Hi.
I've had a rumbling noise and vibration for the last few months that I cannot get to the bottom of. It felt like a drive shaft failure so I replaced what I thought was the offending shaft to no avail. Anyway I've now changed all 4 drive shafts, the gearbox and swapped over the transfer box with a known good one , all to no avail. The symptoms give the exact same feel as a driveshaft failure. The prop has been checked and is fine but we fitted another to eliminate that too.. Cannot think of what else it might be.

I had something like that. Found rear diff oil low, topping up did not help but replacing bearings fixed it. With drive shaft off and back wheels off the ground I could feel it in the half shafts.

Nodge68 · Dec 22, 2016

RealBeale said:
Hi.
I've had a rumbling noise and vibration for the last few months that I cannot get to the bottom of. It felt like a drive shaft failure so I replaced what I thought was the offending shaft to no avail. Anyway I've now changed all 4 drive shafts, the gearbox and swapped over the transfer box with a known good one , all to no avail. The symptoms give the exact same feel as a driveshaft failure. The prop has been checked and is fine but we fitted another to eliminate that too.. Cannot think of what else it might be.

What model FL is it? Didn't you get an FL2?

freelance · Dec 22, 2016

Tyres? Have you swapped them round?

Pompey · Dec 23, 2016

I have had a rumble that is intermittent, N/s can find no problems, had it checked out by a trusted mechanic, he heard the noise once.

The brake caliper on N/s sticks, attempted freeing it 3 times now so replacing it, hopefully that will sort it.

RealBeale · Dec 23, 2016

Tony Reeves said:
I had something like that. Found rear diff oil low, topping up did not help but replacing bearings fixed it. With drive shaft off and back wheels off the ground I could feel it in the half shafts.

I'll let my mechanic know as he's convinced it's steering related.

Nodge68 said:
What model FL is it? Didn't you get an FL2?

You're right , I have an i6 F2. However this is my F1 Td4. I wrote the post at work on my tablet, for some reason wouldn't let me use the function. Every time I tried to put in F1, it just skipped to the text box.
So just so there's no confusion (which is my fault for using said tablet) here's a pic of my troublesome Td4.

Nodge68 · Dec 23, 2016

Have you tested the VCU? How are the VCU mounts? Are they parallel with each other and at 90° to the VCU shafts?

guineafowl21 · Dec 23, 2016

Nodge68 said:
Have you tested the VCU? How are the VCU mounts? Are they parallel with each other and at 90° to the VCU shafts?

+1 I was thinking front prop bearing.

RealBeale · Dec 23, 2016

Yes mounts were tested and are fine. Been on for less than 2000 miles and were not cheap , around £80 each IIRC.
Basically it was an immediate thing. It didn't appear over time or get worse. Just drove home from the MOT in October and as I accelerated suddenly got this noise and vibration - just like a drive shaft failure. Got worse on acceleration and died off when coasting.I've had several d/s failures and immediately thought "here we go again". I've taken it to my mechanic who's had it for about 7 weeks now.

Nodge68 · Dec 23, 2016

My V6 developed a vibration suddenly after I gave it a boot full out of a junction. It vibrated under acceleration from then on. I think it was the gearbox causing it, as it began leaking from the drive shaft. I changed the drive shafts and box seals. The vibration remained however. It was the box or IRD, bit I never identified the actual problem before I sold the car.

Tempus Fugit · Dec 24, 2016

Pompey said:
I have had a rumble that is intermittent, N/s can find no problems, had it checked out by a trusted mechanic, he heard the noise once.

The brake caliper on N/s sticks, attempted freeing it 3 times now so replacing it, hopefully that will sort it.

Had this same problem on mine earlier this year, re-furbished caliper, new pads and disc and all good. Perhaps the same for the OP's motor?

Pompey · Dec 24, 2016

I haven't driven it since we got it back but Mrs P is happy with it, not heard any noise since getting it back.

So maybe worth checking the brakes, we fitted new disks and pads earlier, just for info.

Pompey · Dec 31, 2016

Quick update.

Now driven vehicle on a 265 mile trip, since replacing sticky caliper no noise at all.

Incidentally we also changed turbo at same time as it was leaking oil and did not want to risk a runaway engine. Can't see that the turbo would have created the intermittent noice, but thought worth a mention.

Happy new year

rob_bell · Dec 31, 2016

Good result - and great to have the update

Rumbling vibration mystery

RealBeale

Active Member

Tony Reeves

Well-Known Member

Nodge68

Well-Known Member

freelance

Well-Known Member

Pompey

Well-Known Member

RealBeale

Active Member

Nodge68

Well-Known Member

guineafowl21

Well-Known Member

RealBeale

Active Member

Nodge68

Well-Known Member

Tempus Fugit

Well-Known Member

Pompey

Well-Known Member

Pompey

Well-Known Member

rob_bell

Well-Known Member

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