My Cougar has three slides and none of them has a gutter. I agree that it should be easy enough to install one even if you use 3M auto body trim tape to install it temporarily to see if it works. Is there an owner's club/forum for your brand? If so, it would benefit you to join and post this over there. Lastly, I have bought three RVs from CW. We got great deals but, frankly, their service is bad in so many ways. Unfortunately they have ticked off Cardinal to the point where they are denying warranty payment. Call Cardinal and explain your frustration in CW. Ask if there are other dealers or independent repair places that they will authorize you to take it to. I have no direct experience with your problem, but it sounds as though the slide is not coming in tight enough. Good luck & let us know how this turns out.