Temperamental Reverse!!
 

Hi all, i'm new to the forum as you can probably tell.
I have just purchased a 2001 S8, unfortunately since the cold stint of weather we had my car (when cold) will not select reverse?? Once the engine is warmed up and i have driven for a bit its absolutely fine.

After reading up on the net a bit i decided to change the gearbox oil and filter (have used Audi genuine parts). My mechanic friend helped me to do this and also recommended using a small part of the old oil as using totally new oil may block the filter very quickly and cause big problems. I plan on doing another oil and filter change in about 500 miles.

The car now changes gear alot smoother but i still have the problem!! My friend told me that i need to use the car a bit more to circulate the oil more through the reverse gear valves.

Has anyone else had this problem?? My car has done alot of miles 180K but has a full Audi service history. I only paid 1500 for the car so don't mind spending a bit on it as long as i'm spending on the right thing..:Confused:

Reverse failing is a common problem on the FL gearboxes. It's the Clutch F seal if I remember rightly. You could go for a rebuild or a new box for about £2500 all in which would do you for a good bit longer :)

search the forum for F125 switch. I seem to recall someone having a tempremental switch in cold/wet weather causing some issues might be worth a check to see if they sound similar to yours. If not then unfortunately it could be what he ^ said :C or several other gearbox based gremlins all of which would require a specialist to diagnose properly.

Do all the gear related lights in the DIS display turn red when the problem occurs? If so, it's logged a fault and gone into limp mode - that means there's a stored fault to read.

Doubt it's the F125 switch - this sounds more like a mechanical fault as mine would still work in reverse fine with a duff F125.

I had a duff F125 switch. It made a hulluva noise in reverse and in other gears when cold, but it worked fine. A VagCom would diagnose this. That's the essential first step IMHO

Hi and welcome. What part of the country are you in? There maybe someone close that could plug it in for you and see if it has logged errors.

Oh and photo's of the car please

Hi, thanks for the numerous replies which are very appreciated. Firstly pictures will be up shortly, the car is currently being detailed and paint corrected. I saw the bonnet last night which someone had spent a whole day on!!

the gearbox issue is still present even though the weather has got a bit better (not in the minuses anymore). When engaging reverse there are no crunching noises or any other noise for that matter, and there are no red lights or warnings on the DIS??

Just so everybody knows i am based on the borders of London and Surrey. Any other suggestions before i start shopping around for a new box??

Regarding the F Seal, if this was blown would i still be able to get reverse, as when the engine is up to temperature reverse selects no problem at all??

Hi Mate,

Welcome to the forum. If you want a VAG-COM check done tomorrow, i'm just based in SW18 if you're able to drive it down...it may give some more clues as to what is wrong.

Thanks,

Oli

Hi Oli, thanks for the offer but i'm a bit concerned that the fault will not show up by the time i get to you as the engine will be up to temperature and reverse will engage then. If you think its still worth a go i would be very grateful for the check. I'll pm you my number.

One other thing i ought to mention is when i select reverse the rpm raises by 100 rpm?? Any clues to whether this is linked to my problem??

Could be oil pressures in the gearbox.. The F seal is pretty much working or not as far as I know.

Hi again, unfortunately took the car out on 2 runs today and it seems reverse has disappeared altogether!!! Anymore suggestions would be greatly appreciated....

I suppose to think positively could it not be something simple like the selector position needing adjusting? The bit that joins the gear leaver to the box. You’ll have to get under the car to see. It’s hidden behind a heat shield on the NS of the box.

Might not be but I’d be starting there after a scan

sounds silly but do you have the correct amount of ATF in the gear box ? as it warms up it will expand and then the correct level is there and it will select reverse but when cold only forward gears will be able to be used failing that i would say the F seal on the box have given up the Go, if the gear boxes are serviced every 20k they are fairly good units, i am yet to report any kind of fault on my box and its now on 151k and its still silky smooth, i do a full oil and filter change every 15-20k and keeps it in tip top condition,
i use this stuff every second box service
http://www.wynnsusa.com/pdf/spec-she..._Flush-Kit.pdf

and then follow normal filling and service +++
best i can do sorry

I seem to remember a recall for a gear selector cable. I think there's something about it in the paperwork I got with my car. I'll try to find it

Many thanks for all the responses.++++++

Sorry I can't be more helpful but the invoice I have states "WARCUS Carried out 37D5 update" I'm sure the previous owner said it was a gear selector cable recall

Indeed it was. But it was to modify the cable so that the car could not be started in reverse if my memory serves me right.

Ian will not doubt back the librarian to the hilt with the right answer! :p

It sounds like the reverse seal has died.

Unfortunately it's buried inside the gearbox and is one of the first things go into the gearbox when you build it up from nothing.

MG