I don't know if this means anything at all in regards to your particular problem, but 2 years ago this month I took my '86 300E (194,000 miles at the time) to the local MB dealer (one of the better ones I am told!) because the tranny was leaking fluid. After doing a thorough inspection by their senior mechanic I was told that I should not spend the $2000 to fully rebuild it, but rather to check weekly on the fluid level, top off when necessary and put a piece of cardboard on the garage floor! In essence he told me the tranny in that car is mechanically a bullet-proof workhorse that should go at least 300k miles if not 400k miles if not more as long as the fluid is kept new and at proper levels. 2 years later it is still one of the smoothest-shifting transmissions ever built....and well after 202 thousand miles! Moral of the story is: If, as you say, it is running/shifting flawlessly then the squeak shouldn't be anything to be concerned with. Moral #2: Can you believe a MB dealer would actually tell you the genuine truth and not try and pillage your bank account!