I don't think they sell the pump that way, without the fuel level sending unit. I know you can buy a sending unit separate from a pump assembly, but not the other way around. I did that job once, I think it was on a Chrysler mini-van. I had to replace just a fuel level sending unit as a warranty repair, and it was a huge PITA. For as much trouble as it is and the age and mileage on your existing sending unit, it makes a lot more sense to me to just replace both parts with a new pump/sending unit assembly. That is just my opinion on it. I hate working with gasoline. Fuel pump replacement is a job I only want to do once and be done with it for a very long time.