ATF Change for E420
 

I am the 2nd owner of 97 E420. It has 103,000 miles and no previous ATF (Auto Transmission Fluid) change record existed as far as I know. Three MB certified techs of different dealers told me to machine flush and change the filter and pan gasket ASAP. However, One MB certified tech with 31 years of experience from another dealer told me not to touch it because the original ATF has already broken down with metal particulates. He said it is too late to have ATF serviced becacuse the machine flush with refill of new ATF will cause more problems including gear shifting difficulty and fluid leak. I am confused with whether or not I should have ATF serviced. Any of your professional and technical suggestions to clarify my confusion is really appreciated.

MB's current recommendation is for 722.6 ATF and filter to be changed once at 39k mi.

Previously was considered "filled-for-life".

I'd change it (not flush it) and continue to change it at an appropriate interval.