Transmission Flush Service

I have a friend who wanted to know about getting her Transmission serviced. She has a 98 VW Jetta with 56,000 miles on engine and tranny. She wants to know the correct way to do it. I told her the flush machines at lube shops and such clean out all the old fluid, but kind of strip the tranny in ways, and plus they don't change the filter or even clean it. I told her that she should try a place that specializes in trannys and have for 27 years, that will drop the pan, replace the gasket, and clean or change the fluid in this sealed transmission for over 100 dollars less. the Dealer said they will charge her $255. Any help and insight guys would help.

That is a very different transmission than most as it uses a special fluid and most people probably can't even find the fill and check points. Have her take it to someone familiar with VW's specifically.

what is the special fluid, not like the normal Mercron 3 or ATF+3 fluid, but a special Oil?