S8 with gearbox woes. Code advice please.

[MikkiJayne]

I disagree its the F125 in this case - wrong fault codes. I only mentioned the F125 as a possible electrical cause of limp/thump rather than it always being mechanical.

The codes say something electrical inside the sump to me.

For the record, I have known-good F125s that I am happy to lend to people for diagnostic purposes. If you can change it yourself its worth a try before spending £250 on a new one, but if you have to pay a garage just put a new one on.