My rig is parked outside in temps below 15 f this time of year and rig is only driven 2-3 times a week for a very short time. My parking brake is always set in this situation. I let the rig run a little to warm up tranny, etc. but when I release brake and step on the go pedal, the brake seems to be frozen...then releases with a "pop" only after a fairly hefty load on the accelerator. Anyone else enjoy this phenomenon? Is it normal? Any idea what causes this or what the ramifications can be? Thanks.