2.2 HDi 6spd auto vibration

[jml]

On my C8 2.2 HDi 173 with the Aisin 6 speed auto I have recently detected a slight vibration/shimmying under gentle acceleration. I presume most of the transmission etc is similar to other Citroens with this engine / box.

I have had the car almost since new and it has now done over 160,000 miles so I know it pretty well and it’s only been in the last year or so that I’ve noticed this. It is very slight and anybody driving the car for the first time might well not notice it but as I’ve lived with the car for so long I can definitely detect a change.

To describe the vibration better, I get a very slight sensation of the steering pulling fractionally each way under light acceleration at most speeds and in all gears. I describe it as ‘shimmying’.

Obvious sources I’ve checked have been engine and suspension mountings and wheel balance and tracking. My suspicion now is either driveshafts or the auto box. The incorrect fluid was added some time ago which I have changed for the correct Aisin fluid.

Any thoughts, ideas or experiences of something similar anybody ??

All ideas gratefully received

Cheers

Julian

[jml]

Bump. Anybody ?

Cheers

Julian

[hattershaun]

Hi Julian,

I had a similar problem with a C6 2.7HDi auto (Same basic gearbox as your car).

It felt as though the car was driving over a rumble strip at the side of a motorway, small high frequency vibration. It wasn't all time though, most noticeable under acceleration.
It turned out to be the torque converter breaking up, as confirmed by an auto gearbox specialist.
I had the whole gearbox & torque converted replaced with a good secondhand one by the specialist that looks after my cars.

This car had 90k miles one it when acquired, failure happened soon after, I'm not sure if the gearbox oil had been changed beforehand.

I now do a 3 litre partial gearbox oil change every time the engine oil is changed.
Good practice would be to carry out 3 or 4 partial oil changes as a start to get the oil as good as possible. As well as the 3 litres of oil that will come out with the drain plug removed, there's a further 4 litres held in the torque converter.

Good luck with your car.
Shaun Lilley

[jml]

Not THE Shaun Lilley, from CUK ??

[hattershaun]

Afraid so, The one and only!

[jml]

Ah ha, good to hear from you - JML = Julian M Leyton.

I’ll try to send you a PM

[Harlequin]

Julian - you did ask about fluid chanegs for your box on here - viewtopic.php?t=58134&start=105

[jml]

Julian - you did ask about fluid chanegs for your box on here - viewtopic.php?t=58134&start=105

Indeed. The thing is that using Aisin’s own fluid cured a significant vibration that I had however I do still sense a slight vibration at times which makes me wonder whether another fluid change would be useful, bearing in mind that so much previous fluid is left in after each flush.

[Harlequin]

yes you only change about 40% each time, so really it needs 3 changes to get most of it out

[jml]

Yep, I did 3 flushes but, as you say, it only changes about 40% (7 litre capacity - 3 litres drain and refill) each time.
However, of course, on the second flush, quite a proportion of the ‘newish’ fluid coming out Is still the original fluid. And still some on the third flush but I’ve never got my head round quite what proportion of old fluid is left even after the third flush.
My fluid is still a bit mucky which concerns me. I’ve had a very knowledgeable friend recommend EDT Automotive ( https://www.edtautomotive.com/transmission-clean/ ) to me. They have a special machine that, they claim, will change over 95% and I’m tempted to try them.

[white exec]

There will always be remains of old fluid, no matter how many partial drains and refills are done.
The old stuff just gets progressively diluted with fresh, so should be a dwindling issue.
Three drains and top-ups are probably as much as most folk are going to tolerate.

This has always been an issue on auto boxes with a torque converter, except for the rare (old?) models which used to incorporate a t/c drain plug.