A tank ????

[MIMF]

scductman,

Good question! If Keystone does it the way my employer does it, the vent and drain pipes simply are slip fitted into the top of the tank with gaskets around the pipe. The pipes to fit inside a short collar on the top of the tank.

That is a project that I will be undertaking myself as our galley grey tank is leaking also. I'm going to be working around the rear axle as the floor plan that our Challenger has is the same as the 3400. And I have been doing the same thing you are.