If the tranny is fine............then leave it alone! The first most common problem with these trannies are leaks, only you can make up your mind if it is something you can live with. As far as "life expectancy" it's a crap shoot. If the proper maintenance was done, including fluid and filter changes, then you have a sporting chance. 'Cause even with that all going in your favor, the other determining factor is abuse. Hard driving versus easy going will shorten the life of the tranny. And if you are still under the impression that these MB autos are the greatest in the world and never break down..............I have some beachfront property to sell you in Kansas! I only own one of these cars because I'm a mech.........no labor costs. If you can't work on 'em then be prepared to pay, to play. I rebuilt my tranny for a paltry <$200....................."It's good to be king."