This issue first came up for me on my 1999 MB E320 with 90,000 miles which was having very slight slipping. I took it to a transmission shop, who drained the fluid, and put it back in and told me I needed a $3,500 rebuild. I opted instead to have the fluid and it helped the very slight slipping. I did it again at 110,000 miles. I got 3-4 years of near perfect driving from those 2 fluid changes before I sold the car to my mechanic who says the car still drives great.

We bought the E53 in 2005 and changed the tranny fluid approx every 3 years or 30,000 miles. It it now at 90K+ miles, however we live in a hilly area of Los Angeles so there is extra wear & tear on the car. As a %, very little highway driving.

I'm in the camp that one should change the trans fluid on a regular basis. The reports of failure shortly after a change may be true, but the trans might have failed anyway.