My dishwasher was leaking right around the diverter motor. I replaced the diverter motor thinking that was the problem but when I got in there, I saw the rubber grommet and I figured that was the problem. I went ahead and replaced the motor but the leak continued. The manufacturer discontinued selling the $5 grommet because they are evil :-) and instead only sold the entire sump which was a pain to replace and $50 to boot.

Before I went that route, I removed the diverter motor and then treated the grommet with Permatex spray sealant from inside of the dishwasher. I put 5 coats which took about 10 minutes as you only wait about a minute between coat. After about 30 minutes, I also turned the dishwasher over and sprayed the sealant from the bottom a couple of coats as well. Then let it sit overnight. I reinstalled the diverter motor and ran the dishwasher through a couple of cycle the next day and not a leak in sight. Not sure how long this fix will hold but think it's a worth a shot. This stuff has worked good on a oil leak underneath an old car I had so I assume it will last some time.

Worse case scenario, you end up replacing the entire sump anyways so this is at least worth a shot before going that route. Certainly won't hurt anything other than the sump you'll already be replacing and is leaking anyways. Good luck!