Shouldn't be loud at all! We need to go through and check over a few things.
-Make sure your not getting vibrations from your mounting bracket via the frame rail or floor of the truck.
-Check every connection possilbe on the suction side of the pump. Loosen, reseal, retighten if needed. Air entering the system will cause the pump to become loud.
Give myself a call (Anthony) 573-694-5155 or Matt at 573-694-8833. We will help you figure out what is going on.