Riding yesterday and sled goes into limp mode and the temp lights are flashing right after a break. I shut it down and check the cylinders, she's hot but the line coming off of the tunnel is cold. Pulled T-stat and it is open, throw it in the snow and it closes. Pulled off the line at the T-stat housing and start it up...just a dribble coming out. All signs point to the pump but I have not done an AC pump. Looks to me like it is down on the bottom front of the engine. Are they gear driven? How big a deal to change? Am I missing somthing? Thanks in advance!