The shower drain on the Winnebago Travato 59G model is a strange animal. It drains water to the grey tank, but because of the position of the shower relative to the tank, and the vehicle structure that in the way, a suction pump is used to pull the water out of the drain and send it to the grey tank. That pump is slightly inconveniently located under the bottom board of the cabinet under the kitchen sink, which generally collects a lot of miscellaneous necessities for travelling, making it difficult to access.
It sounds like this complexity should simply be a managed by an easy flip of the switch to power the pump when you're showering. However, there are small amounts of clothing fibers and other particulate matter that are washed down to the drain, and these can easily clog a suction pump. To protect the pump, there is a small mesh filter connected to the pump inlet that strains out the gunk first. This filter is unfortunately small and full of water when it finally fills up to the point where it no longer drains - which makes for a mess when removing it to clean it out. The solution to that is to add a filter washer to the drain in the bottom of the shower - but that being even smaller of course ends up needing to be cleaned even more often, and small bits still get past that first filter and end up still clogging the small filter.
I've been thinking for a long time on how to improve this situation. Ideas I've considered include removing all the filters and taking a chance on the pump clogging, or possibly still working but at a slower rate which would still be acceptable; also reworking the plumbing to bring the drain tube horizontal above the van floor and then into the grey tank, eliminating both the pump and the filters. Each seem problematic and costly.
Instead, I've come up with an alternative option as at least a temporary measure to reduce the frequency with which the small filter must be cleaned. This involves adding an additional much larger filter (strainer) before the original one, and thus eliminating the filter washer. The filter I choose to add is this one:
SHURFLO 1/2" Raw Water Strainer - 50 Mesh Screen
Which is available at the amazon link above, or from other locations at possibly a lower price. It's not cheap, but it's the largest one that I can find that still has the same 1/2" fittings that all the existing plumbing connections use. In addition to that, I also picked up a 1/2" nipple (short 2" pipe with threaded male connection on each end) from Home Depot (available at most hardware stores).
This is the video of the installation process, which is fairly simple (remove the input hose from the pump, add the new filter and nipple, and reconnect the input hose):