Hi mate let me chime in, experience tells me to scan all ecus just incase an engine fault is upsetting the trans but sounds like you did, good on you. Ok let me know what the code is that you have now. Is the gearbox 096 or 01M?? you can tell with VCDS top left hand VAG number on the trans 02 screen. Foils go bad on these mate, thats the foil that connects to the valve body it gets brittle and cracks after time, also check the very small pins in the multi pin connector top of the gearbox, common for green corroded terminals and they can be open circuit.
Just a couple of pointers for ya, grab the code
Cheers
Jmac