So I'm confused. Never looked closely at a 50 series or newer design. But I'm assuming even with the gear driven pump there still must be a fan belt that would also turn the alternater of course. So does the fan run independently of the water pump off the belt, or is it driven off the water pump gear driven shaft? Just gonna take a wild guess but I had some literature around here at one time on the 50s, and I know they had increased fuel efficiency over the 40s. I remember somthing about a variable speed fan. So mabye running the fan independent of the pump was part of achieving the better efficiency. Any input anyone?