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View Full Version : Please Help Erratic Downshifts



RCaine15
30-10-2023, 09:52 AM
Hi All,

I'm looking for some help please, i have a 2008 A4 Avant 3.0tdi and i'm having an intermittent issue with the auto box, Sometimes when i'm slowing down i'll be on the brakes and my box will be changing down, it can drop all the way down to 1st even when i am not a complete stand still, this makes pulling away again a bit of a roller coaster as sometimes the box will be in the wrong gear for the speed i'm travelling. The issue doesn't happen all the time as most of the time it will change down fine and when expected i have noticed though that when this issue happens when i eventually stop the car and turn it off there is still a fan running in the engine bay as though it has been running really hot, this can happen if i have just completed a short journey (school run) and the car hasn't even got up to temperature according to the gauge so it can't be overheating?

Anybody got any ideas as to what this could be and how i might go about resolving this? it has been into a garage but just my luck that when it has gone in they can't replicate the issue and it has performed faultlessly whilst there, they have plugged in and can't read any faults related to this, i do have other faults that im working on with the car.

Crasher
30-10-2023, 02:29 PM
What is the VIN?

RCaine15
30-10-2023, 04:03 PM
Wauzzz8k39a079644

RCaine15
31-10-2023, 01:42 PM
Has anybody got any suggestions?

Crasher
01-11-2023, 12:20 PM
KXS box of the 0B6 series (a ZF 6HP28 AF), awful things but not as bad as the 0B5 which is an abomination. You could try a full flush and filter change plus have it plugged into ODIS to see if there are any software updates or a TPI about the issue, I can't see one on my offline system. I have known people fit a new mechatronic but that is a £4788 part and if it doesn't work you were half the way there to an Audi exchange box at £8773.20, which would be a crazy thing to do. Personally I would suggest a filter and fluid change and if it doesn't help, live with it/get shot.