Ok, so a few years ago I put in a laundry room upstairs. I put this on the opposite side of a bathroom. I put a tee in the bathtub drain and added my washing machine drain to that. Works pretty decent except for it gargles and spits out a little into the tub during the drain cycle.
I recently had a leak with my washer so I opened this wall back up to investage and I'm thinking of redoing this drain (hopefully more correctly this time). I'm also thinking about adding a drain in the floor in case I have future problems with overflowing, etc.
It just so happens that there is a vent pipe that runs horizontally through this wall that I could tap into if need if it would work better this way.
How should this really be plumbed? I can open the ceiling down stairs if need be to tap into other drain like the one for the toilet, etc.