I have 120,000 mi on my 99 EVC and I have had the ATF fluid changed 3 timess at
Santa Monica VW, last time they charged me $178.73 for:
AT AUTOMATIC TRANSMISSION FLUID - FLUSH AND CHANGE WITH SYNTHETIC FLUID
Labor was $105 and parts were
1 - TF Synthetic ATF 42.90
1 - 1Gasket 26.45
1 - A Pipe 2.68
1 - B Seal 1.70
Next to the the engine, transmission repair or replacement is probably the biggest cost risk you could have. If you can find a competent shop that will do the procedure for a couple of hundred bucks I believe it is well worth the expenditure.
Good luck,
Larry
LA, CA