Yes you must have had the drill going clockwise instead of the correct counter-clockwise rotation. I also have a melling HV pump in my 440 and when I primed it my drill slowed right down and oil psi shot right up. My drill could barely keep spinning and started smoking. Even with the drill barely spinning the gauge read lots of pressure. Now that the motor's back together and the car's driving it's got lots of oil pressure, works great, although to be safe with the higher capacity pump I did do a 7 quart pan/pickup.