2003 A4 Avant 2.5TDI Quattro Gearbox problems


Registered User
Sep 17, 2011
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Hi all.

After some advice, Have a 2003 A4 2.5TDI Quattro SE with 95k on the clock.

Had an oil leak recently which was a simple fix of replacing the oil filter housing 'o' ring. I then decided to degrease the engine as it was saturated with engine oil.

I noticed there was a lot of oil sitting in the 'v' of the engine so put a fiar bit of degreasant into the area and flushed it all out with copious amounts of water. Lovely, all clean and non-stinky.

Everything was fine and we went on out 1000 mile, weeks holiday top Cornwall.

Now, the above may have nbothing to do with the problems we are now encountering but here we go.

On the way back on the M25 noticed a very minor judder while cruising along about the 80mph mark. Had filled up with diesel in Cornwall and suspected I mayh have got a duff batch from Tesco.

However, this morning I get up to go to work nice and early and go out and start the car. Nothing obviously wrong initially. I then make my way out of my drive and off downt he road happily. Get to the m,ini roundabout at the end of my road and notice a fairly extreme thump as I try and pull away. Carry on up the road and the gearbox seems to be taking an age to change gears, leaving itself out of gear in between the changes.

I continue my journey and it gets worse and worse until it stays out of gear between changes about 2 seconds, then drops in with a thump, it won't progress past 3rd and will just keep revving and increasing speed. I can change gear with the steering wheel buttons but the 'gap' is still there between the gears.

I then notice that if I acclerate a bit harder (was taking it very easy by this point) that in 5th there seemed to be slipping (as if the clutch was slipping in a manual box)

I pulled into a layby and found it to be dragging at idle and that the engine was idling at 1300 revs rather than the 900 I'm used to.

I nursed it to my place of work and called the AA who turned up, plugged ther diagnostic thingy in to find no engine ECU faults but were unable to read the gearbox ECU.

At this point I also noticed that when I turn the ignition on the glow plug light does not go out any more at all and stays on. The engine turns over for quite a few revolutions before firing and that it still idles at 1300 revs.

I had the car recovered to my mechanic (independant but extremely good (SLP Auto's, Boreham, Chelmsford) and they plugged their diagnostics in to also find no fault codes on either the engine or the gearbox.

Now I read a lot of these types of posts but nothing seems to cover my problems specifically.

Could the degreasing and lots of water have got into some electrics somewhere in the engine bay?

It seems odd that two problems have occured at exactly the same time but I know this is a possibility.

Would a high idling engine cause issues with the gear changes? Ort is it more likely that the gearbox has gone FUBAR and is messing with the engine idle?

All thoughts much appreciated. The car is still in the garage and will be looked at on Monday but any guidance I can give the guys down there will be very welcome.

Thanks all!
Welcome to the forum!

Not good :(

Has the car been scanned with a full VCDS system or an aftermarket system?

I assume you have the tiptronic gearbox? It's hard to see how the water problems would manifest themselves now, 1000 miles later. Have you checked the plenum chamber to make sure it's not got water sloshing about in there which might have damaged the ECU?
Hi, thanks for the welcome.

I think it is the tiptronic, has a PRNDS with a sideways selector to + and - as well as the up and down buttons on the streering wheel.

No idea about the plenum chamber, where roughly is it, and what's it look like?

I would have thought that if an ECU had got soaked it would come up with some error codes though, no?

Don't know about the VCDS system, the plug in computer was green and had Bosch written on it. It also seemed to be able to see what various solenoids/actuators were doing. Looked like it had lots of settings/data to sort through. Was reminiscent of my laptop when I used to program the ECU on my Toyota Celica GT4. Which reminds me, must get it up for sale to fund this gearbox repair!! LOL!
We have an 03 tiptronic and recently learned that the gear boxes are not supposed to need servicing.The chamber is under the battery and is prone to filling with water if the drains block.I check mine regularly by shining a torch through the cover to see if its dry other wise its easy to remove the cover and look around.Could be that in flushing with water some got in there and it may be flooded.Hope its not the gearbox cos it s/b OK with that miles.All quattro autos are Tiptronic
Does the auto/triptronic box have a Hydraulic motor, I have seen these starting to fail and giving slow gear changes. The ones ive seen, its the bushs on the motor that drives the pump that wear out.

Just a thought but no idea if its the same for the audi's
Righty Ho!

Thanks for all help and suggestions, fortunately it turned out to be cheap (relatively)!

First the Air Mass Meter was replaced which fixed the gearbox issues, then the coolant temperature sensor was replaced to remedy the high idling engine.

However, the car now changes gear like it's been lubricated and tended and cared for. It's sooo smooth, so obviously the air mass meter has been playing up for a while!

So, all sorted for £250 inc vat. Not bad, certainly better than the £4300 for a new gearbox!

Thanks for all your help!