When it was -10F it took a few minutes for it to stay down on its own. At 20F it seems to take a few taps.

Does anyone know if it is causing the rear pads to drag when it is this stiff?

Not so much to protect your tranny, but to address the fact that the Renesis doesn't have enough compression to hold the car if the incline is steep.
On my driveway (which is so steep that the doors won't stay open), leaving the car in first without the hand brake will lead to the car lurching down the driveway one rotor turn at a time.:p