I have the opportunity to purchase an A type OD unit from one of the guys in my club. It was "running when removed" but has been sitting for a number of years unused. It has been drained and fluid was clear with no "chunks". How do I spin it up to test it before I make an offer? I understand you can use a flexible coupling and a 1/2 in drill?? How many RPM and what direction do you spin it in? Any and all advice would be greatly appreciated. I know these boxes are considered "bullitproof", but I do NOT want to make a costly mistake on something as important as this.