Originally Posted by Cosmik Debris
I'd suggest everyone check that their pump wasn't installed with rigid pex hose directly from the output side. With a copy of the shurflo install guide in hand it may be a warranty mod, since it isn't supposed to be hooked up that way.
Good luck. I haven't seen one from ANY manufacturer that isn't hooked up that way from the factory. On our current TT and our pop-up, I installed a couple loops of nylon washer hose and mounted/isolated the pump on rubber. That silences it very well. I added the accumulator to alleviate short cycling the pump and the constant rattling off the unsecured pipes. Between the two, I can barely tell it is running.