Ted, mine had to have a little downward adjustment at the factory when it was new because it raised a bit on the outside. I think there are some adjustment bolts on the slide frame that gives you a little vertical latitude.
That didn't totally stop the leaks in a heavy downpour. So what I learned to do is lower that side of the coach with the HWH jacks a small amount when it was raining hard and that solved the problem. I use a carpenter level on the floor when I adjust the level the coach after the HWH system automatically stops. If the driver's side is a wee bit high, I just drop it so it's a wee bit low, if I think it's going to rain hard, and that does the trick for us.
Former Owner, 2006 36MDDS
2010 Arctic Fox 22GK Travel Trailer
2007 Toyota Tundra