I use 90wt in my three speed overdrives. From the spillage I got when transporting them from their orginal owners, it looked like 90wt was used by them. I'm not saying that 90wt is the only lubricant to use, just that it seems to work fine for. Also, I can't say that I have had much difficulty in the winter. Although St. Paul is farther north from me (about 10 miles actually).
