PartSelect Part Number PS5136127
Whirlpool Part Number W10537869
I have a Kitchenaid dishwasher model KDTE 404DSP0.
The unit started leaking and the problem was a worn seal around the shaft of the diverter motor (numbers above). When the unit is running you can see the leak coming out underneath with a flashlight. It comes out of a yellowish white plastic tube that is right underneath the shaft of the motor.
PartSelect is a fine company but in this case they don't sell just the replacement seal. They want you to replace the whole sump with the correct seal to the tune of $125 where individual seals are from $1.50 to $10, if that.
I was not going that route, to put it mildly, so I made my own seal by purchasing a sheet of red rubber at Ace Hardware in the plumbing department and a tube of non-hardening #2 gasket sealant. The rubber is easy to cut with scissors. If you have a punch you can punch out a circle, mark the center with a pencil, and drill a center hole with an electric drill. You'll need to expand the hole with the drill bit. I used a rat tail or round file to shape the inside diameter to where I wanted it. You'll have to have a snug fit to ensure no leakage.
Use the old, defective seal to mark the approx. diameter of the new seal. Shape the outside diameter with a dremmel sanding head but hold the seal firmly or it will fly off into the air. Make the new seal fit snugly. Not too tight or too loose. Apply some sealant to the (dry) bottom of the well in which the seal is placed and on the side and edges of the seal. Tiny bit is good but make sure the bottom part is completely covered. This is awkward as you'll have to lean over the door into the interior of the dishwasher and work with a flashlight. A toothpick works to apply the sealant. Wipe off any you get on the shaft.
Let it get tacky for ten or fifteen minutes then apply a small amount of silicone grease to the shaft of the diverter motor and inside the seal. Slip the seal down into the well and press firmly in place with a blade screwdriver. You're done.
I've had no leaks since I tried this. The video at this link shows how to get at the seal. No need to pull the unit out of its cabinet. You can do everything from the top without doing that.
Obviously, I'm going to have to keep a close eye on the bottom of the dishwasher for new leaks in case I didn't fit the washer correctly. You can fashion a tray out of a plastic gallon milk jug to put under the diverter motor to catch minor leaks should they appear down the road.
"Xcleen" is a v. good cleaner to run regularly. It removed a lot of caked soap first time I used it. I didn't realize how important it is to deal with the caked soap.
"Lemi Shine" is another dishwasher cleaner. I used it to soak the filter I took out of the bottom of the tub. It was unbelievably caked with hard soap residue and the cleaner gradually loosened it so I was able to completely clean it up. Be careful so you don't damage the wire mesh. A toothbrush is useful for those last remaining specks of soap crust. You don't have to replace the filter periodically now. You can rejuvenate it.
Hope this helps.