How often do you need to change the transmission fluid on a 1998 Mercedes Benz 500sl?

The book says one thing, every MB mechanic says another. More late model MB's need trans repairs than just about any other one item on these cars. Every 50,000 miles is when you should service the trans. I think MB suggests something like 100,000 miles...WRONG! These are sophisticated units now with 5 and 6 speed trans'. There's more going on inside than you can imagine. If you can service these transmissions every 35,000 miles...do it...that's once every 3 years. My brother works for MB, and I have a 2002 SL500 and I recently had the trans serviced...it makes a big difference. And do yourself a favor...only have factory MB techs work on the trans....they know better, besides, they have to sync it up to their computer, which most independent do not have because of the expense...otherwise, you're only getting 1/2 the job.