Since BMW has since annouced the need of doing a final drive oil change at 600 miles, I decided I should try and do it myself as my dealer is far, far away. Besides, I am at 2500 miles now so maybe I should do it now instead of waiting for the 6K service. Dealer never did it at the initial 600.
The oil plug faces rearward at the 3 o'clock position. The fill is where the speed sensor is nearest the rim. The CD manual shows removal of muffler, wheel, brake caliper, speed sensor, and top torque arm bolt allowing the final drive to pivot downwards so the oil will drain out of the rearward facing drain plug.
Doing all the above, I could not get the final drive's drain plug to point straight down to 6 o'clock position. Seems the final yoke on the drive shaft will not fully disengage from the final drive spline allowing it to drop straight down.
In the manual it shows a puller to get the decorative black cap off the lower pivot point of the drive (drill out and use slide-hammer puller!). So that seems to be a expendable part one needs to have on hand, plus one would have to reset the preload of the final pivot bearings. On the old RT, one needed to use a torch and a 10 foot snipe to break the damn (Locktite) pivot bolts loose. Ugh!
Without messing with the lower pivot assembly, at best the plug would only point down to around the 4 o'clock position. The drive isn't heavy, maybe about like an 8 pound bowling ball. The rubber boot is held in by some sort of thick white grease with an internal expanding ring verses the external boot on the old RT's. There is no room
to insert a small hose in either hole to suck out the old fluid. The crown gear is too close to either hole.
My best attempt was to use an extra quart of oil and do a series of 4 flushes. I put the drive back up and put a screwdrive in the upper torque arm to hold it up. Put in maybe 150cc of oil (side of bottle), spinned it by hand, and dropped it to allow as much as would come out. Repeated the procedure for 4 times. At the end, it came out pretty clean (clear yellow).
Yes, the old was dirty and had what appeared to have moly-disulfide in it. It was a dark color near the bottom of the drive. Uppermost fluid was clear as it came out of the hole initially when I first pulled the plug. I found a Amsoil rep. in the phone book white pages and he sold me a quart of their 75-90 weight (GL-5) oil for $10.30. Seems Amsoil is just about sold as Amway Products (i.e. individual salesman).
The other odd thing was I could almost loosen the wheel's Torx bolts by hand! Dunno what was up with that? The old 4-bolt RT wheel was a bear at times to loosen, but it had a higher torque setting as well.