I replaced the pump assembly today. It was pretty easy and not too nasty. It definitely solved my leak and it pumps dry much better. It would be about a 10 minute job but I did not have the intructions as they sent me instructions for the complete unit with bowl. Also I stuggled getting the old hoses off (and back on) for several minutes as there is not a lot of room to work.
As you can see below the flapper valve in the base of the old unit was broken. I am really pleased. I have a better, safer, fully working Twist N Lock for cheap and little work.
One caution. The unit is shipped in foam peanuts. I had to disassemble the discharge so I could turn the fitting to line it up with the discharge house. I found 2 of these huge peanuts inside. I am pretty sure that would have been trouble.