Thanks all for the replies. There is no leak from my base gasket. The water comes in from the air conditioner unit as it drains into the trailer instead of on the roof. I wish this unit were mounted up front as the spec shows allowable down slope of 20 degrees as opposed to 5 degree up slope. My guess is that Carriage used the wrong air conditioner or mounted it wrong to begin with. I bought this trailer when it was 6 years old and it had never been used so it was never caught.
I will build the wedge myself out of plastic and see how it works. If not, air conditioner shopping.
By the way, I tried to post a picture of the instruction manual showing the wedge but apparently my computer and this forum do not play well together. Can't figure how others post pictures as I follow the instructions to the T.