It was leaking between the seal and the electrical housing. A kit could have repaired it, but the cost wasn't that much less than just replacing the entire pump and it was a lot easier that disassembling it which requires a special tool I did not have. Airstream told me it would be replace under warranty if I could prove it wasn't a leak caused by freezing-which of course I could not. Their quick answer made me think it hadn't been the first time the question had been made to customer support leading me to believe this is a common issue to fail.
Originally Posted by wayneskid
Did you determine what the failure mode was with the macerator? In my case one of the short studs that held things together broke off in the housing. I am guessing that this happened due to water freezing inside the housing.