A couple of weeks ago, my car had a weird little shudder at just less than 25 mph, especially when under load. Changing the brake-lamps seemed to put an end to it, and all seemed well.

Until yesterday...

* In full-auto transmission mode, the band of speeds at which this occurs has spread to 18 to 35 mph;
* The shuddering is along the front-to-back axis of the car;
* The amplitude of the vibration has increased dramatically and I'd say it has a frequency of 2 to 3 Hz - the whole event is like someone is firing a WW1 Vickers machine-gun out of the rear window;
* There are no other speeds at which this happens (I have tested it to XXX mph ). In fact, it is as smooth as anything;
* It only happens when the car has been a few miles, not when cold;
* The only faults were thirty-one "low-voltage" faults and a few recording lack-of-comms between ECUs. I have assumed the latter relates to the former and, in turn, the former relates to the use of the winch;
* By staying at a constant speed with some load applied, e.g., driving up an incline, it is possible to get it to continue all the time the throttle is applied;
* I have observed that, whilst its happening, the rev-counter needle is dropping up-and-down by about 50 rpm and at the same sort of rate as the shuddering;
* No smoke;
* By using command-shift I can get the shuddering to occur at different speeds - with similar, but not identical, rpm to when when it happens in full auto;
* All fluids at the correct levels;
* There aren't any 'mechanical' noises, e.g., grinding, banging, etc.,
* No sign of any leaks;
* It got a new - good quality - battery last year;
* The brake-lamps still work(!).

Any thoughts about where I should start looking? Recording some OBD may be possible. An initial thought of mine is a sensor going out of range; another thought is that I have somehow created an earth-loop by the wiring to the winch.

I had planned to do some off-roading this weekend but, after quite a few miles through rural Herefordshire at about 30 mph, this problem made me sufficiently concerned for me to return home.

TIA,

Hugh

?t=38

Quote:

* By staying at a constant speed with some load applied, e.g., driving up an incline, it is possible to get it to continue all the time the throttle is applied;
* I have observed that, whilst its happening, the rev-counter needle is dropping up-and-down by about 50 rpm and at the same sort of rate as the shuddering;

This sounds to me like the dreaded torque converter problem.  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Agreed

Ho, hum. Oh well, after a bit of Googling, at least I now know what a lock-up clutch is.

Recon box or box of matches?

A new TC is probably all that's needed if the problem is relatively recent.

When I had mine done, they found the output splines were worn so a new output flange was required. That requires everything to come out of the casing as it's mounted from the inside. And it also meant a new transfer box input flange too as that was worn - which means splitting of the transfer box. Got a new transfer box chain put in at the same time. It was suggested that the vehicle had done some serious towing (or towing badly (shunting the transmission)) in order to wear the splines. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Cheers, Wayne. I will go down that route.

Is this likely to be a body-off job? From what I've found on the internet (which, as we all know, is always correct), it seems to be possible without, but only by masochists and/or Mr Tickle.

Don't think so.

Just add a tube of Dr Tranny Shudder fix to your gearbox oil, sure the problem will be fixed. That stuff works like a charm, it already fixed my fluctuating ref-counter issue.

+1 on the Dr tranny. My X5 had the shudder 5yrs ago so I did a trans service and put in some Dr Tranny (is that a PC name these days..) and its been fine ever since.

Dr Tranny will help but the issue is caused by contamination of the torque converter clutch surfaces, so it's not a "fix" merely a cover of the symptoms.

Hugh - the gear box is dropped from below so body isn't removed. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Slightly in trepidation at what a search for "Dr Tranny" might return, I was surprised at how overwhelmingly positive the reviews are. However, I can't understand how it helps the LUC problem so I can't believe it either. What I don't want to happen is lots of dwarf or assorted crud to find its way to the valve-block.

Thanks, Wayne - a couple of videos on YouTube make the removal of the gearbox look like a real palava. It is booked in for a repair at a highly-recommended specialist. They wear brown shop-coats - a sure sign of competence, if ever there was some..

Here:-
It may well buy you some time. Many have said that it has sorted their issue for a substantial period also. Have a read and make a judgement call.
Personal experience of two tubes is good.

https://www.ebay.co.uk/itm/LUBEGARD-AUTOMA...SwEeVZeZub 2011 MY D4 HSE
Previously 2001 D2 TD5, 1996 D1 300Tdi, 1985 90 2.2 petrol.
Bikes! KTM, BMW, British, Classics and others.

How much of a pain is it to put it in the gearbox? There are effectively only two weeks between now and it being fixed and most of that is in the same gear on a motorway.

From memory of other threads, jack the vehicle up on the side what has the gearbox fill point (so that the oil doesn't run out) squeeze in the lube additive.

If the TC is being done in a couple of weeks, I probably wouldn't bother, to be honest. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed