I purchased a replacement pump and check valve.
I was able to remove the lower cover panel and access the pump without having to remove the dishwasher. I disconnected the hangers, the discharge hose, disconnected the electric plug, and remove the larger connection. I disassembled the pump to check and it seemed okay. The old check valve flapper was gone. So I replaced the check valve.
When reinstalling the pump, I found it best to start by connecting the larger black hose to the check valve. I put the clamp in the final position and squeezed the clamp to get it fit. Not much clearance through the lower access panel. After the big hose was connected, the electrical, drain hose and hangers were fairly easy to connect. All said, I was able to complete the job in less than an hour.