I think I have it tracked down but I was going to put in some additive that I just got delivered from amazon anyway. I got tricked into thinking that if the coach was drifting out of level, it has to be the jacks or the valves to them. I checked those out and all was good. Then I noticed it only happens when the slides are out. I verified the Hydac valve to the slide was good. I then pulled all the slides in and then closed all the needle valves to the slides except one and moved the slide all the way out. I did it for each slide, one by one, waiting a day or two in between. The level only drifted if I had the bunkhouse slide out with only that needle valve open. I'm guessing I've got some internal leak by in the bunkhouse slide cylinder (I'm not losing fluid so no external leaks). I am going to try the additive to see if that helps. If not I'll have to decide if it's worth the trouble to drop the chloroplast and replace it. Wouldn't you know the bunkhouse was the last one I tested. When I opened the needle valve after closing the other two, the slide moved a little so I suspected that would be it.
By the way, I do appreciate your input though. Who knows, this may still not be it.