I´m using grease only in capsuled gear boxes f.i. my 307G2 has one and the 133K3 has two. My 111G156 and the 29K71 get my favorite S-761 oil. As Shoepatcher said, grease holds dirt, lint and so on. Oil in best case and when used frequently will wash out some of the dirt. I still oil my 133K3 about twice a month no matter if I used or not (stupid hum?) as some of the bushings still "spit out" some old dirt bound in the oil that is dripping from the machine.