The gears in a winch are not high speed, they do take a lot of pressure but they are not spinning at some crazy rpm. The research I have done recommends CV grease because it is light weight, heavy grease is not recommended due to it not staying put and tends to glob up and can actually make free spooling difficult or impossible. Having said all of that I just rebuilt/cleaned my new to me Warn X8000i and I used a light marine grease (due to it being less affected by water?). The winch works great since the rebuild. In my research it was stated a kazillion times that the tendency is to over grease things, the recommendations that I saw was to just use a brush (I used an acid type brush, the same disposable brush I use to spread wood glue when I build furniture) and just filled in the gear teeth the width of the brush (about 3/4") all the way around each gear. When I reassembled it and moved the gears through several revolutions the opposing meshed gear squeezed the grease over the entire width of the gear set and pushed some out the sides. This worked well for me, YMMV.