I know it is late to answer for I had the same problem-- my bedroom slide was leaking bad. At first I took the moldings off to see if I can find the leak. No such luck. Upon inspecting further inspection on the roof, I notice that my awning on the slide out was torn loose (threading come out) and this made a funnel that poured all the water into the gasket causing the gasket to come away from the side of the motorhome and thus the water was pouring into the top of the slide out into the bedroom.
I re-inserted the gasket and sewed the awning back in place. NO further leaks.
This may or may not be your problem but might help other RV's with a leak problem.