I leave mine in drive. I've noticed, like Cab said, the shift rpm drifts up a bit from the first run to the second run when it gets hotter, then stays about the same from there for the rest of the day. I notice it more in the cool days of late fall more. If I warmed everything up better it might not happen.

I don't know the answer to your question. But I have a steel drum and ultimate sprag and will probably get a blanket before I go back out again.