Took my sled to valemount this wknd and couldn't pull more that 7900 rpm on dick hard snow. Rode it 3 weeks before in Revy in balls deep pow and was pulling 8250 all day long. The only thing that was done between that time was a new drive shaft installed by Polaris. I took it for a ride across my yard back home in ab and could pull 8200, normally it's pulling 8500 at home. Anyone else having this issue??