I have a 2018 RT. After reading about many GS owners with rusty splines I decided I would service mine. I do all my own maintenance. Dropping the final drive is a snap. Removing then reinstalling the rubber boot, also no problem. At 60,000 km the spline area, within the boot, was nice and dry. I uesd Honda Moly 77 on the spline and reassembled. As per Boxflyer’s instruction I generously regreased both ends of the rubber boot with lithium grease to form a nice seal from the elements.