Kestas,

With my other vehicles which use Dexron III I change the trans fluid at 30K intervals because the fluid is not synthetic and there is no drain on the torque converter - about 1/3 of the fluid is actually changed.

With my Mercedes the fluid is synthetic and since I can drain the torque converter I was able to change over 7/8 of the fluid. From my experience changing trans fluid on vehicles, I find that the initial fluid change is the worst as far as the fluid being discolored and the pan magnet being very dirty. The subsequent fluid changes the trans fluid is still red in color and the pan magnet is only slightly dirty.

Another reason to change the trans fluid on an earily build 722.6 trans is that Mercedes did not use a pan magnet, I have installed a pan magnet when I changed the trans fluid. I recommend installing the pan magnet away from the trans filter pick-up since the pan magnet will attract the magnetic sludge. If it was located near the trans filter pick-up the trans filter could suck-up the magnetic sludge and reduce the amount of fluid flow through the transmission.

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Ray
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles