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

Originally Posted by andeck

In 5th, it is really quite a terrible sound and vibration!!!

Welcome and that description suggests it is unlikely to be a normal low rev situation.
Drive shaft bearings and uni-joints have been known to fail but it could be quite a few things.
If it's as bad as you describe I would be getting it checked by an experienced mechanic.

Scott

I would give the guys at MR auto in Redcliffe a call,they probably will have a good idea what it is.

I don't have their number with me ATM.

Could also be the gearbox.

Aaargh i misread the op. I would suggest at that speed there is a TC issue or a tailshaft centre bearing/ rear universal joint on the way out.

Does the rev needle flicker slightly. This doesn't happen all the time, but keep your eye out for it to move a little bit up and down, genuinely around the 1200 - 1800 rpms, whilst you are putting the foot down. I had a rumble, which i also described as felt like the car was in the wrong gear when asked to perform, especially below 2000 in a higher gear under more load when towing.

Turned out to be a Torque Converter failure.

Hi guys, thanks a lot for your input. Had a service by MR the other week, but didn’t get them to test drive it in this situation so they didn’t pick it up. They were very good and very thorough with the rest of it, with pages of findings and suggestions. Great guys there too and good communication!!


I will watch for the needle flicker, thanks for the tip ozzy.

Sounds like it may be something pretty major though, so will take it back to MR and get them to test in that situation specifically.

Suggest you check " known faults " at cars. Com as could be the subject of a known fault
Requires some balance weights fitted to fear box as it is a resonance problem ( check behind rear bar under the car and you will or should see two sets of cast weights hanging off the chassis) commonly referred to as "the balls of a D4" ;-)

Justinc, I received and email notification and thought your original message was reassuring. Haha just due to all that 3.0 litre torque!!

Ozzy, I noticed yesterday that while driving in sport mode, probably 5th, when I applied the right amount of right foot, the rumble started and then the revs kicked up a few hundred revs and it went away. I assume this was the torque converter unlocking, as the gear didn’t change.

If the torque converter is locked and the revs are low, I’m thinking that it is just too much ask of the engine and it is perhaps engine related (knocking or mount issue etc), and hopefully not torque converter itself.

Bobc, it definitely has some balls!

I saw a reference to a balance weight affixed to the transfer case, is this what your were pointing out? LTB00305NAS3

Wrong rev range unfortunately, would have been an easy fix!

Ssm72928 sounds bad regarding the bearing failures, but it is 280 something k kms so should have failed long ago. No oil light at this stage! 🤞

Hi Andeck,

I travelled a few thousand kms towing (on a holiday road trip so couldn't do much about it) with what I since found out was a faulty torque converter. I'm not saying your is the same, but a few symptoms I can share are these:

• at low speeds and low revs (towing or not towing) and then applying just a slight amount of power there was rumble / almost engine shudder / strained
• generally these sounds and shudders were noticed between 1400 - 2000 rpms
• the car felt like it was in the wrong gear. If you're familiar with driving a manual, I would describe it like you would want to shift down a gear just before the engine stalls
• on only a few occasions I noticed the rev needle flicker. Between 1400 - 2000 rmps when I put slight pressure on the accelerator. It was a noticeable wobble up and down. This didn't happen very often and probably needs a specific amount of speed / load and acceleration to cause it. But if you see it, you'll know what I mean
• you can power through the rumble / shudder by putting more acceleration on and above 2000 rpm everything is ok again.
• at highway cruising this rumble is much harder to pick up

I'm not sure how to get the torque converter tested, but if not too expensive and you can associate with most of the above I would say worth having a look.

My mechanic was very quick to diagnose the issue for me based on these, but the agreement was immediate by his asking of me, had i seen the rev needle waiving / flicker slightly up and down.

New converter, total flush of oils and steel pan at the same time.