D4 SDV6 rumble low rpm high load 5th/6th gear

Ozzy, thanks heaps for the details you’ve provided. I will have to keep an eye on the needle but so far have only seen that slight increase in rpm as mentioned above.

If you can remember.... when this occurred, would the output from the pedal have shown a request of 30% change to 40% and hold there or would it have shown a continued climb of requested acceleration? Hope that makes sense.

Graeme. Thanks for that nugget of info, will make sure if it needs replacing that I go for the updated version.

I have started getting a really similar problem, a hum/vibration noise from the rear left over 100km/h. Have had the wheels balanced and rotated thinking it might be a balance issue to no avail, but I guess next I need to get bearings etc checked out.

Hi Ben,

Sounds like a bearing or something specific to that corner. Try sitting in the back and listening. Are you sure that that specific tyre was moved to a different location? If they balanced and put it back in the same place, it could be tyre cupping or something which will not go away.

The noise I hear is definitely from the front of the car and can be felt through the front wheel wells.

Good luck with your troubleshooting, hopefully something easy!

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Originally Posted by andeck

Ozzy, thanks heaps for the details you’ve provided. I will have to keep an eye on the needle but so far have only seen that slight increase in rpm as mentioned above.

If you can remember.... when this occurred, would the output from the pedal have shown a request of 30% change to 40% and hold there or would it have shown a continued climb of requested acceleration? Hope that makes sense.

Graeme. Thanks for that nugget of info, will make sure if it needs replacing that I go for the updated version.

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From memory everything behaved normally under strong / committed acceleration. No rumble, shudder or rev needle wobble. The revs climbed and dropped smoothly, as expected.

Most noticeable issue and description I started out with to the mechanic was that the car felt like it was straining (hence the rumble sounds) and the best description I could come up with was, "if it was a manual drive the engine sounded (which I could feel coming through the cabin) like I needed to change down a gear, otherwise it would stall. I know that is less likely in a diesel, so referring to petrol drive in this instance. This was typically encountered at lower speeds and soft acceleration requests. I could easily 'power through' these rumbles and shudders by more aggressive demand for power. There was no obvious loss of power or performance and no ECU dash warning symbols. According to the computer the car was fine, but I had lived with her for over 130k kms, so I was thinking otherwise.

The rev needle flicker was not common for me. I reckon maybe spotted it 3 or 4 times over 6,000 km trip. But the first time was such an unusual sight that it stuck in my mind. As soon as the mechanic asked me and waved his finger slowly between 2 & 4 o'clock (or 8 & 10 if you look from the other side) I knew he had confidently understood my suspicions that something wasn't right.

If you are in a high gear (typical driving) at low speeds (eg 40 - 60) and you softly ask for more the rumble (could feel like a shudder) is most obvious. It sounds wrong and the car feels wrong.

If you have AT tyres, they don't help with separating the noise and feelings though.

hope this helps.

2-4 o’clock.... so flicker was around 1000rpm? That’s a massive amount. I noted a little movement the other day of maybe 100rpm up and the back again, no where near that much though!!

When you powered through, did the sound go away when your foot went down or did it remain til revs got to 1800 or so? Mine will rumble until revs climb to 1600-1800 irrespective of 50% request or 100% request.

Quote:

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Originally Posted by andeck

2-4 o’clock.... so flicker was around 1000rpm? That’s a massive amount. I noted a little movement the other day of maybe 100rpm up and the back again, no where near that much though!!

When you powered through, did the sound go away when your foot went down or did it remain til revs got to 1800 or so? Mine will rumble until revs climb to 1600-1800 irrespective of 50% request or 100% request.

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Sorry, no. I didn't mean it flickered / waived that much. That was just the mechanic's prompt when he asked me did I see the rev needle move up and down when it ought not to be. And so that's how he waived his finger.

I reckon the flicker / waiving was about 100 - 200 rpms. I recall somewhere within the 1400 - approx 1900 zone. It didn't move that much but like i said, it was very odd to see. The reason I felt it was a bit odd, being the engine sound and vehicle performance didn't mirror the rev needle waiving. It shouldn't be going down when I'm asking (although only softly at the time) for increased power.

The rumble and, as previously said distinctive shudder, was most apparent 1400 - 1800. Add more assertive power and you get through it once the revs get to 2000 and it all goes away. The faster you plant the right foot, the quicker you get through the rumble.

Sounds like you might be heading down the torque converter path too.

Any idea if you can get these things tested ?

Thanks again for the info ozzy. I know something is wrong. I recon quite a few people out there, having read this thread, have since gone out and tried this scenario out! [emoji6]

I am going to carry on driving and see if it gets worse, as at the moment i very rarely hear the noise when the box is doing its own thing.

I found the brochure for the 2011 D4 today and it shows the torque/power curve if the 3.0. It is putting out 600Nm by 1500 rpm, so maximum stress on the converter.

Thinking this though, when it kicks up a gear it would still be putting that much load through, but with more power as well. Wonder if it could be possibly vibration from a mount issue or resonance throughout the drivetrain and vehicle... will have another look around and also check trans fluid level.

https://www.aulro.com/afvb/images/im...018/04/217.jpg

I should add that I’m not disregarding your input in the least. I am probably looking at a torque converter, but I’m being very hopeful that it’s not!! [emoji16]

I've got a 2007 D3 and have a similar issue when I force the car into a higher gear than it wants to be in.

For example, if I'm cruising along a suburban arterial road at 60km/hr, I've been experimenting by upshifting to 5th. If there's a downhill slope and the car isn't having to put much effort in at all, you don't hear any rumble. If it's flat or slightly uphill, it'll make that rumble while it's in that 1200-1400rpm range. It does go away once you have a few more RPM on the dial (say, by dropping back to 4th).

I'm not terribly worried about it myself – my guess is I'm demanding a bit much from the engine at extremely low RPM; it's only occurring when I upshift into a gear the car doesn't automatically want to be in.

Thanks for the input ndrew. Guess we are both either safe or heading towards some problems. At least not alone! Haha

I am still working on isolating the issue. I’ve done a few things but next I’m going to bolt a weight onto the transfer box and see if the noise changes. Perhaps the tsb 305nas3 may apply despite the different rpm range.

I’ll let you know.