Anyone use 5-40 Rotella in a Polaris Ranger? We have a 2005 700cc XP with about 350 hours on it. The manual says synthetic 0-40 and we have been using Mobil 1 0-40 changing it each 100 hours with good results but wondered if the heavy duty oil would be better. We probbly don't need the "0" as our garage does not get below 32 degrees. We use Napa Gold filters. Thanks!