gmakishima

Yep, from what I understand the formula for the ATF hasn't changed much from when transmission fluid changes were recommended and when it became "lifetime" fluid. I think you either change it at or before 50K miles or not at all because there is significant sludge like build up in the transmission by the time 100K is reached. By changing the fluid at 100K, you will be introducing fresh detergent that will dislodge some of the build up which could end up damaging your transmission. Even if you flush first, some of the build up will probably remain and will most likely be dislodged later, damaging your transmission.

It's kind of like if you use low quality motor oil with poor detergents and there is sludge build up in the engine. When you switch to a better quality oil with better detergents it can actually hurt your engine by dislodging the built up contaminants into the engine.

ADD

+247k

When I sold my '99 528 last year, it had 247,000 miles on it. I didn't do a damn thing to the transmission. ever.

Ran like a top, and still does. (Sold it to my cousin)

InfiniteVT

I think 67k is a great time for a transmission fluid change. I'm new here to the E60 board because I'm interested in getting a used one sometime, but I had an E38 for 5 years and it had a ZF tranny with "lifetime transmission fluid." After seeing the horror stories from folks that either didn't change theirs or changed it with non-BMW/ZF fluid, I changed mine twice with the OEM fluid and filters. Once at 100k and then another time at 130k and it ran like a fine swiss clock, as they say. The key to a successful change is to get the right fluid/filters/etc and someone that can do the procedure correctly. I had both of mine done at well regarded indy shops that specialized in Euro cars or BMW's. With my next BMW, I intend on doing a tranny fluid change around the ~60k mark and then again at ~120k. I can't stress enough that you need the correct fluid, do *NOT* use any substitutes or "compatible" fluids with the BMW automatic transmissions.

As a followon, I would follow the advice from the ZF service manager, mentioned above. It is the most sensible sounding and is in line with my previous experiences: