2000 Astro van is a leaking boat in the rain!

Lovely teal color. Strong back and front bumpers that do not dent with minor accidents. Great side mirrors but as with all vans there is still a blind spot. Ease of movement on sliding side door but why doesn't everyone have doors on both sides? I have issues with the back door. When the top back door is up I can't reach the outside handle so I grab the strap beneath the top door to shut it and twice (about two years apart) it slammed down on my hand deforming my fingers more each time. This van all of a sudden started leaking when it rains and the back of my van gets very wet (and then stinks). I usually keep the back seat out so I will have more room for my groceries or wedding cakes and now I have to keep a plastic sheet spread on the back to keep every thing from getting wet. We have searched every where for the leak(s)and have put that clear caulking all the way around the back door and the roof and nothing has stopped it. My 1995 Astro was much more roomy in the front and back seat and it never leaked. I had it longer and enjoyed it more. Other than the terrible leaking and the back door and the cramped leg and head room this van runs extremely well. This is my third Astro van but I will never get another.