Many Winnebago owners have found windshield leaks due to rusting of the metal frame that the windshields are glued to. I had a dealer repair mine a couple of years ago ...and that was a very expensive and time consuming disaster to put it bluntly. I believe the source of the water was a leaking clearance lamp, which the dealer did a very sorry job of repairing (not to mention the sorry job they did of replacing the windshields and the mess they left of the wipers, etc. Next time I have a problem, I will use Permatex Silicone Flowable Windshield & Glass Sealer, available at most auto parts stores. The rubber on the outside of the windshield pops into a channel that is secured with double-sided tape (a pretty sorry setup). I would remove the rubber, apply the flowable sealant where needed, then re-install the exterior rubber as required.
Paul (KE5LXU) ...was fulltimin', now parttimin'
'03 Winnebago UA 40e / '05 Honda Odyssey toad