I had to replace a pump in a previous trailer. Replacing a pump is one of the simpler RV repair jobs, and I know how to do plumbing very well, so the time and fuel costs it would have taken to transport it to the dealer to get it fixed weren't worth it.
I replaced the bad pump with one of these:
SHURFLO® REVOLUTION™ Pump 12 VDC 3.0 GPM | REVOLUTION™ 4008 Pumps
It runs virtually silent, plus it has an adjustable bypass. That means the pump just turns on and runs when the pressure drops below a certain threshold - no cycling when using just a little water and therefore no pulsing water. I'm not sure whether it's more efficient to run all the time or keep starting/stoping the pump. It's probably the former, so it may not the best option if all you do is boondocking and/or dry camping, however. A pressurized accumulator tank would probably work better for that.