So welcome to my world of insanity….

I have a a 2008 A6 C6 2.7tdi Le Mans with 163k on the clock it has a ZF GWK 6speed auto (See attached pic of build sticker in the boot)


Why the “insanity”? Well i think ive read every post/thread on every website to do with a gearbox issues and none match my situation, well not 100% and so ive bitten the bullet and decided to ask as im stuck!!!

2 weeks ago my car decided without any warning or any prior issues to not want to move at a set of lights, went into gear fine just wouldn't pull away. Had it recovered and taken home (after causing chaos at said lights for two hours).
i had to go away with work for two weeks so car was sat at home unused for that time.

I got back Friday and started the car and low and behold, it drove!! It was sluggish at pull away and did show the rev gauge seemed to flutter when throttle off but other than that, silky smooth gear changes and pulled like a train, as per norm

That said i had ordered, while away, a service kit for the gewrbox, new filter and gasket inc 9ltrs of oil from ZF at the cost of 248 quid shipped from Germany and yesterday i done then the service and the car runs fine but dose have issues still…

upon draining the sump i got 5.2 ltrs out, oil was like water and black, not a dark brown but black!
pan was filthy but no filings, magnets were just about visible as they had so much gunk around and on them but again, no mettle. The filter was date stamped Nov 2007 (build sticker states built dec 2007) so im assuming its never ever been touched in its life even though service history say its been done back at 90k!?

anyways, cleaned it all out, refit new supplied parts and refilled as per instructions… now ive ive filled it with 2.8 ltrs first fill, ran and cycled, rechecked and put in another 500ml, ran the car around for a fee miles, rechecked and got a further 250ml in before overspill. So in total approx 3.5 ltrs and i cant get anymore in as ive checked it again this morning and its dribbling as soon as i loosen the fill plug so its full.

been for a drive and the car seems slow to pick up from stand still for about 2-5 secs it revs then moves off and starts to accelerate as normal with butter smooth gear changes but when you lift off you can see the revs fluctuate/pulse up and down when throttle off but you cant feel it in the car. There is no “shunting” when selecting gears but if for example you pull away from a stand still and just move forwards say 50 yrds and then throttle off you can hear a sorta rattle and a slight (very slight) vibration in the cabin. Apart from that it drive ok but im loathed to start using it again as it dont seem right and dose not drive as well as prior to the traffic light incident. None of the above were present before the traffic light incident and ive done best part of 80k in it without issue until that day.

Now before i get asked, its been scanned with VAG and Autel and just to be sure Snap-on diog equipment both prior to and after service and NO fault codes present not even now.

So basically chaps, any ideas as i love the car, its truly immaculate inside and out and its like a old mate to me, been everywhere and never ever not once, save for this, let me down but i need to be realistic, is it time to let it go or can it be sorted if i throw some money at it?
Can this particular gearbox be “reset” in someway?
Would or can a secondhand gearbox be put in without much effort and or would it need programming if i did?
Was it overfilled in the first place and damage done because it was?
Have i now under filled it as i cant get 8.9 ltrs in the bloody thing!
Finally, why would ZF send 9 ltrs when only 3.5 is able to fit or correct?


Thanks in advance
Gel