I own a 2000 sp 500 and my son has a 2000 Trailblazer. I know Polaris fluids (ie: oils and hub fluid and trans oil) are VERY expensive. What are the brand names and weights of fluids you found that work well, also aftermarket oil filters for both? Someone told me to use synthetic oil in the Trailblazer trans fluid? Is this right? Any help is greatly appreciated. Ride on.............