Thanks chamberman! I was wondering if it was a check valve or regulator or something as opposed to the pump itself. Seems like it's all one unit anyway though. How was your experience dropping the tank and swapping it out?

 

Yes, its an all in one unit from what I remember. I believe that the check valve must be built into the pump assy itself. The tank drop isn't bad as long as you take the time run as much gas as possible out of it. I thought I had it pretty well empty but it still had about 3 - 4 gal left in it which made it a bit unwieldy to get out by myself. I managed to handle it okay though. After I replaced the pump assy I had my wife come out and run the jack to lift it back into the car. I laid under the car and made sure everything was clear on the way up. Not a bad process, it took me a Saturday afternoon to do the work.