Originally Posted by TN road dog
Sounds like several Montana owners have the same problem. Running a silicon bead across the top edge seems to have worked for more than one owner. However, as Renagade1LI found a lack of sealant around the frame,this sound like the real source of the problem. That’s a lot of work, but if the silicon doesn’t hold On mine I’ll investigate the same and make a permanent fix as he has.
Its not that bad, remove a screw and slide the door off, remove the screws securing the frame and its out. scrape off sealant if any, apply butyl tape & install. I added matching self tapping screws so the frame does not move, I did use small quick grip clamps to lightly pull the frame against the wall. I let the butyl set for a week, removed the excess & used extra flex silicone to seal the top & sides of the frame. One year later no leaks, and it only took an hour each, easier than you think.