I replaced my water pump a year ago... It was really noisy / bouncy and a small drip now and then. I focused on finding one as quiet as possible. After I got it out I opened it up and nothing was broken... It was just cheaply made. I put in an accumulator tank almost identical to Ron's (it was hard to find room for it on a 2900D! ) and very happy with it. Since my accumulator tank is under the bed I extended the air bladder fill thru the filter cap compartment so that I can check and adjust the pressure without opening the bed frame.
This is the pump:
RecPro RV Water Pump Direct Replacement For Shurflo 4008-101-A65 3.0 GPM | 12V Water Pump | Self-Prime | Camper Water Pump | RV Plumbing
https://a.co/d/dIx1tOoIt is super quiet. Now I actually have trouble knowing when the pump is running unless the RV is completely silent.
I lined the entire slide out under the bed with Uxcell 1cm foil faced black foam insulation or 1 inch foil faced foam board. The new pump is on top of the uxcell insulation and the screws are seated in the slide out floor. It's solid, but a small amount of cushion remains btwn the pump and floor. There is no added insulation on the bottom or inner walls of the bed... As I wanted as much indoor temperature transfer as possible to keep the pump and pipes warm in the winter. I have survived a week of Illinois winter with lows of 12F and nothing froze. To me,,, this slide out was the most likely place to freeze so I made an extra effort to stay warm while I had the bed apart. A side benefit is that my water tank stays cooler in the summer if the AC is on. Nice.
Pictures of under the bed and the outside air valve included below.
You might also consider replacing the pex connector seals if you see any damage. I always keep a few of these on hand.
Adabuing 16435 RV Plastic Santoprene Swivel Seal 1/2" Replacement for RV Shower Freshwater Hose Pex Fittings Replace, RV Bathroom Valve fix Your leaks -(14 Pack)
https://a.co/d/5Gyb8mrFeel free to ask questions... Not sure how much info you wanted here.
Larry