After having had a nose at the photo MJ posted, it reminded me of my gearbox woes which I've cunningly hidden in the Engine/Under the bonnet section here:
http://forum.a8parts.co.uk/showthread.php?t=7550
Your current situation as described seems to be very similar to mine - my A-drum has some of the top lip destroyed, which was discovered when it went to KSM in Carshalton, Surrey for a rebuild. I was able to select reverse no problem, and it went into limp-home mode aka thump mode upon selecting drive. The thread posted above contains plenty of pics. When my gearbox went 'bang', I drove it for 13 miles back home from Gatwick, and then 3 miles to Carshalton where it was going to be repaired. Auto gearbox man told me to take it steady and not rev it too much - seemed to be quite happy on the way back home. Traffic light starts were of a glacial pace, at best so I used my hazard warning lights to good effect.
I hope it's not terminal for you - it was the enthusiastic and caring response on this very forum that persuaded me to spend the money and get it sorted. I'd have only possibly experienced the exact same issue if I were to have gone out and bought a replacement car of a similar age.
Hope all goes well and keep us all posted.
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2010 B8 S5 Sportback quattro 3.0 Supercharged in Sprint Blue (current girlfriend)
2000 D2 A8L quattro 4.2 in Audi silver (my ex-girlfriend)
