My 2 speed above ground pool pump will only run consistently in the slow speed. If placed on the high setting, it will run for about 25-30 minutes and then stop. The high speed cannot be used again until the pump has been turned off for a while, then the same circumstance repeats. It will always run in slow speed, even when the high speed side of the switch is inactive. The motor runs quietly. It never seems to be more than just warm to touch at any time. I can't hear any evidence of bearing noises. It is not tripping the breaker or the GFI. It's about 2 years old, never had any problems until this just started happening yesterday. Any thoughts?