In my TM, bedroom slide, I also had water trouble. I fixed this by changing the rubber seal overlap at the top of the slide out so the upper one overlapped the two side seals. I then glued the corners tightly together, and no more leak.
Worth a look.
07 TM 40D;ISL 450 Cummins(upgraded). Very happy w/coach
Gnarly toad to scoot around.
Geocaching, hiking, fishing, National Parks, Civil War sites.