More gearbox problems
 

As some of you may know, I've just bought James' (mkoneman) S8, but I've got gearbox problems within 48 hours of picking it up. :(

This morning when I selected reverse gear, all the gear indicator panel lit up (I think that indicates 'safe mode'?). But after a couple of restarts and a run to the end of the drive, it was fine again and did the 30 plus mile trip to work with no problems.

But when I left work tonight, the gear indicator panel was fine, but it wouldn't change up from 1st gear, either automatically or on the tip. Again, after a short run and a couple of restarts, all was fine again for the journey home.

What on earth is going on? And is this an expensive fix?

Could be the F125 switch is a little corroded, especially if it's been sat for a while in this cold and wet weather.

Happy to do a scan of it for you, or just swing by A4 and see what codes come up.

From what you've described I'd tend to agree with Psyche. I had similar symptoms after my car had been laid up for 12 months. It happened twice and has been fine since but it scares the crap out of you when it happens.

Vagcom will show it as a fault. Fingers crossed for you that's all it is.

If you can find the 'is it curtains for the box thread' Adrian E had a similar problem with his.

Yep, sounds just like mine when I first bought it a year ago after it'd not had much use for a good long while!

I would suspect the F125 switch, and it will show up on a scan if it is that.

There's 2 different versions depending on VIN and it costs about £160 for the part plus a ball-ache in labour to swap it as there's bugger all access so the box needs dropping off its mounts to get it low enough to come off. Mate that did it for me reckons there's more space around the box on an RS6!

Mine used to come on about 1 start in 10 and was usually more likely to kick in if I had to move the car back and forth before I set off properly. Once in D and working OK I'd not get any issues. Likewise I had mine decide it wouldn't shift out of 1st or 2nd until I cycled the ignition.

Since changing the switch (along with the gearbox oil and filter) I've had no problems whatsoever with it :D

Adrian

Could be the F125 switch as others have said, but the car hasn't been used for a while, which could indicate something else. IF a scan doesn't show a fault, don't panic.

I had this exact problem as you describe when I bought mine 18-months ago, and cured it with a new battery after three weeks of ownership. Since then, it hasn't put a foot wrong.

I figured the battery charge wasn't enough for the sensitive ECU - no matter how often I drove the car. I have only done 5,000 miles in that 18-months, with the car laid-up for 6-months at one point... Problem never re-appeared :)

It does sound like electrical problem not the box itself

F125 switch replacement is shown on audipages HERE Jim if you want to know whats involved +++
its the neutral safety switch and will be either 8 pin or 10 pin in type. 8 Pin ones are £204.69 + vat on Etka and 10 pin ones are £113.12 + vat and include extra pins for the reversing light

Thanks for the help again guys. This morning it was all OK again, but I took it into A4 Audi anyway. Right enough, it's the F125 switch with an intermittent fault. I'm tempted to leave it for a few days and see if it it sorts itself out. Do you think it's possible that, now it's being used regularly, that the switch might clean itself up? Or is it only likely to get worse?

Glad you've got that confirmed Jim and hopefully it's easily correctable. Dan Mac who did try cleaning up lhis in the Audipages article said " The old unit did not work after I cleaned it very well, and the new unit worked 100%." so you might find you still get the fault but at least you know what it is in the meantime should it do it again. +++

Could be that some moisture has gotten in and a good few drives will work heat through it and clear it out, along with regular driving will keep it dry, but at least it should be 'cheap' to fix.