While exploring how to do a power steering fluid change, I turned my '99 Ranger's steering wheel from lock to lock with the engine off. It was rather tough with the wheels on the ground, but it went side to side. I didn't drain anything, as I was at the auto parts store in the parking lot. This was probably a dumb thing to do. I've seen that turning the wheels side to side helps work the fluid out of the system when the engine is off

I started the truck up, and the power steering pump started making noise as I turned the wheel and the truck vibrated as I backed out of my space. The groaning and vibrations when I turned were somewhat loud, initially, like air got in the system. On my drive home, the groaning and vibrations while turning went away. When I got home, I popped the hood and found a blowout of a very thin fluid on the driver's side, near and below power steering pump. Some fluid also got on the filler cap for the reservoir. The fluid level wasn't really any different than the other day. Now, the steering is fine, except for some vibration if you turn the wheel quickly from side to side on center. The fluid leak does not seem to be on going. What happened?