Past couple of days of rains caused water to leak from the windshield into passenger side rear floor and that flooded the TCU.
Car drove ok for some time and then transmission slipped, thats when I noticed the flooding.

Now the transmission will not go into reverse. I hear clickling/stuttering from the engine. The drive mode appears to be limp.

Neighbourhood mechanic says
* TCU needs to be replaced ($2000!!) and for AUDI's it has to be a new TCU. An old after market TCU cannot be reprogrammed. Is that true?
* transmission may have to be rebuild. ($5000!!!)

I read several threads at this forum about flooding and damaged transmission.

Questions:
1. Will just blow drying the TCU help ( i read it is a low voltage device so should come back up again)
2. Do I really need a new transmission or will the new TCU just fix the issue.

Before the leak the car had no transmission problems at all. Ran great!

Please advise asap. I am on the verge of considering to junk the car.