2010 Roadtrek Mercerator / Pump

We just had this problem with our 2010 Winnebago ERA also while we were on the road. Not sure if your setup is similar, but the clearance was an issue for us. We did drive up on blocks to get additional room and were able to take off the pump from the tank side and verify that there was no blockage there, but were unable to get the outbound side disassembled. It is as expected a messy, stinky job. According to other posts we've seen, the blades inside might be troubled by hair wrapped around them. Items as small as olive pits can also disable them. We were forced to go in for service and have the pump replaced. Cost for pump and install was around $500. Had we been able to do it ourselves, we would have taken the pump apart to see if the blades were affected. With the new pump, the sound is totally different so we suspect that it hasn't been working at peak for some time. Best of luck.