Well, I finally upgraded my TV -- to a 2010 Expedition EL Limited. This vehicle is equipped with rear air suspension/leveling. I just finished a very long process of setting up the WD Hitch. Wow. This was quite the process for me. I started this new thread for others that might be venturing into air suspension, and you can see what I did to set up what I currently believe is a good fit.
1. WD Hitch -- Camco Eaz-Lift. 800lb spring bars.
2. My goal was to have the front of the truck back to level with only WD hitch, and air suspension off -- to make sure that not to much weight is being put on the leveling system.
Well, after toying around, I think I got it. Below are few pics of what I to do with my particular vehicle to get it where I wanted.
My New Ride
After doing all the normal stuff (trailer & truck level, measurments, etc...) I found that I needed the ball to be just under the tongue. When I had the ball level with tongue or just above... the air suspension would push the trailer a little high above level. I like to ride with the tongue just below level...a smidge nose down.
Final result: with truck leveled only by the WD Hitch, I brought the front of the TV about 1/2" from my front center height marking. Rear of TV is still squatted 1 1/2" low.
Final pic with Air Suspension on: Rear of truck back to my original height marking, and the front of the truck now at 1/4" of the original height marking.
I found that now matter the load, the truck was always going to push back to level, so I had to make sure that my hitch was set right and my TT didn't push high. Also, I see that I have to manage the ON & OFF of the air suspension... as it can be difficult to remove the trailer, as the truck will chase it up as you jack the weight off (bags filled extra pressure).
Quite a fun and interesting morning (and previous evening..) just trying to think this thing through... as I couldn't get it right. Currently, I believe I have succeeded. I leave out Monday on the TV's maiden voyage with the Roo... I guess I'll see.
If anyone else has any wisdom and experience, I would appreciate the input; i.e. dealing with an auto leveling system on the TV. Hope this thread helps somebody out.