Pulling the dishwasher, it was obvious we had a slow leak under it. We had a slow leak from the diverter motor area in the sump. Sure enough, it looked like the gasket around a shaft had to be the culprit.
The gasket was attached to the sump assembly, or the motor. We took a chance and ordered a new sump assembly for a mere $90 and went for it.
All of the trays had to come out. The lower spray arms. Then the distribution runs to the middle rack arms and upper rack arms. Finally, the original sump assembly could be removed - it's a formed plastic part with a rubber seal, held in place with three rotating clips. Taking that out was easy enough.
4 motors had to come off the original sump assembly - disconnect all of their blade-type quick connections, free their wires from retention clips. You'll want a T15 and T10 torx bit to remove that diverter motor. The rest were either quarter-turn screw-on connections, aside from a spring loaded band around the main waste hose and then the main motor that had a rubber hose attached with a crimped band. This last band had to be un-crimped to release the hose.
All of the motors, a sensor or two, and retention clips had to be transferred to the new sump assembly. That crimped band for the main motor didn't look like it would hold up if re-crimped, so we picked up a worm-drive band clamp from the hardware store.
With all but one motors reattached (the last one won't clear the opening for the sump assembly in the bottom of the washer tub) the assembly fit into the hole easily enough. It has an alignment pin towards the front, though I had marked the tub and old sump with sharpie reference marks, just in case.
Alignment was easy, but it took some muscle to compress the rubber gasket to allow the sump clips to seat the assembly.
With that in place, I just had to reattach and secure wires to the right motors - I had taken a photo first and all wires are color-coded per motor.
Reconnecting the waste line was simple. The supply line did NOT want to seal well. It took a couple of attempts to make sure it wasn't leaking, along with running the washer while standing upright and tightening again, to be sure. If only manufacturers used metal fittings instead of cheap plastic ones...
I set the trays back in their glide hardware, set the filter and cover back in the sump, and then dropped in the lower spray arms.