The Eaton Fuller filter uses a scoop that is quite close to the PTO drive gear to force oil through the filter. Since the filter replaces the PTO cover the element cannot be changed without draining the oil. Genos recommends mounting on the RH side but I also noticed in the Eaton Fuller application guide that in some other applications the filter mounts upside down on the LH side. One other thing about the filter, since it must be close to the gear it won't work with Fastcooler's.
Jared