I changed my rear tran. on my sportsman and I used 75-90 weight. I rode it that night for about 20 miles in the snow. Then I checked the owners manual and it calls for 80-90 weight gear case lub. Should I change it or is 75-90 ok to leave in?

 

Opps! I think you need to check the manual again. That stuff can be used in the front gear case, but the transmission uses Polaris chaincase oil. It's also ok to use 0W 40 motor oil.