Leaking Back window

[sportsman]

We purchased a 2010 26rls 5th wheel cougar this spring. The back window has continually leaked in a heavy rain. It drips inside from the top seam where the inner and outer window is screwed together. I have removed the outer caulking and recaulked the window as well as caulking anything that looked suspect on the roof. I can run a garden hose on the window and it doesn't leak so I am thinking it must be somewhere else. Anyone else had this problem?