Interesting article on BMW automatic trans fundamentals . . .

[gale]

Covers both ZF & GM automatics (1.7 Mb .pdf file):

http://www.bmwmotorsports.org/BMW_docs/transfund1.pdf

[George M]

Thanks for the download Don. Interesting read as you say. FWIW in the E-46 community, there is an inordinantly high failure of the ZF 5 speed autoboxes prior to 100K miles. Many believe including myself is that these failures are associated with BMW's lifetime fluid policy which they recently revoked no question due to public outcry about prematurely failed autoboxes. Reading the article you provided drives home the complexity of these units and how critical having clean fluid is for long term function of an autobox.
Thanks,
George

[John B.]

BMW came out with Lifetime Fill in their motorcycle rear drives a couple years ago replacing the previous 10,000 mile change policy. After a number of those L/F rear drives blew up they told their dealers to drain the fluid at the 600 mile service. Hopefully the owners will have enough sense to change the fluid on a regular basis thereafter.

According to the service records that came with the 95 525i Touring I bought last month the fluid/filter was changed in the GM tranny at 30K & 90k. I just did it again at 137K & the pan was clean with only minor sludge on the magnet. The fluid was still red but darker then new. I plan to do this every 30K or every two years as the tranny shifts beautifully now and I'd like to keep it that way for a good, long time.

[George M]

BMW came out with Lifetime Fill in their motorcycle rear drives a couple years ago replacing the previous 10,000 mile change policy. After a number of those L/F rear drives blew up they told their dealers to drain the fluid at the 600 mile service. Hopefully the owners will have enough sense to change the fluid on a regular basis thereafter.

According to the service records that came with the 95 525i Touring I bought last month the fluid/filter was changed in the GM tranny at 30K & 90k. I just did it again at 137K & the pan was clean with only minor sludge on the magnet. The fluid was still red but darker then new. I plan to do this every 30K or every two years as the tranny shifts beautifully now and I'd like to keep it that way for a good, long time.

Hi John,
Glad to see you are still around. BMW lifetime fluid is the worst joke in the industry.
E-34 tourings rock. I know Scott H built one a while ago with a big six that he has even tracked...lol.
Lets hope we see above freezing temps soon...lol.
Best Regards,
George
P.S. Since you are a big Beamer motorbike owner as well, below is a pic of one I would like to own some day.

[ryan roopnarine]

nice find there, don. i've always wondered what the transmission number designations stood for.