Upper slide leaks are often a result of the long "blade" seal, between the sidewall of the main body wall and the top of the slide-out roof, rolling over when the slide moves and leaving a gap. The slide topper should protect, but if it's windy, the rainwater can blow under.
I had the problem with our dinette/living room slide, caused mainly because the slide topper had rotted away before we bougth the MH. I also found the same issue on the bottom seal of the bedroom slide, but that was sealing out critters rather than rainwater!
In both cases, I also found that the seals were coming away from the inside walls at the corners. I got some of that 3M weather-strip adhesive and stuck them back down - no problems since.
I did have to take out the cabinets above the dinette and build replacements, as thet got a mold infestation where the water had soaked in. I would at least take the carpets up to see how much water damage (if any) to the floor has occurred.
Frank Damp -Anacortes, WA,(DW- Eileen)
ex-pat Brits (1968) and now ex-RVers, as of 08 Dec 14.