Written by the SilverBuffalo on the BMWLT.com website.
A few days ago someone asked: how do you change the transmission oil? So while I was doing mine today I took a couple of pictures, just to help some of the new guys out.
The only “special” tool required is a 14 mm allen wrench, you can pick up a set of three ½" drive at Auto Zone for around 7 or 8 bucks, some entrepreneur is selling that same set on E-bay for $25. I ended up knocking the allen wrench “stub” out of the socket and using it with a 14 mm box end wrench. An empty oil “bottle” cut up makes the draining process a lot neater.
remove the right side riders foot peg plate, three allen bolts and two torx screws.
Remove the exhaust system “hanger” bracket two allen bolts, one directly underneath the drain plug, the other is accessible from the left side of the motorcycle, look way up under there and you’ll see it.
There you'll find the transmission "fill plug". Loosen the drain plug, slide a 14 mm box end wrench over the allen socket, now shove the allen socket up into the drain plug and “break it loose”.
Position the “modified” oil “bottle” under and continue loosening the drain plug.
You can carefully measure out 600-750 ml or 20.3-25.4 oz of gear oil or you can just fill it until the fluid “overflows” out of the fill plug, the proper fluid level is even with the bottom of the fill plug.