Hello Dan, After tearing down my fan gear box I have found my basic problem, most of it being neglect or maintenance deficiencies from the previous owner. The angle gear keyway has slightly worn and this has created a sloppy backlash problem with the fan in respect to the belt pulley. Since I have partially disassembled the drive and determined that the seals indeed do leak, I have taken the task of rebuilding the entire unit and going for broke to keep the original design. I wasn't too keen on the idea of reinventing the wheel in the first place! The only problem I have run into as of today is removing the blower fan itself, the service manual depicts a unit which has either threaded puller holes for a two or three jawed puller to exert force for fan removal. Apparently I have a earlier model 853 and the puller holes cease to exist on mine. Any ideas on how to remove this style of fan without breaking it, looks similar to carbon fiber or some sort of composite material. Thanks, JL