The rear shocks should be under warranty, assuming of course the truck is still under warranty.

I am unaware of this "self adjusting" shock on an ML. You must be thinking of a car with ASD or something, not ML's.

I like the tire pressure on ML's at right around 32. Kind of a tradeoff between comfort and carrying capacity. If you really have to load it down, put 35 to 40 in the rear tires, but for a full tank of fuel plus 2 or 3 passengers in the back and a little extra cargo, 32 at all 4 seems fine. It'll improve the tire mileage and fuel mileage over the 28 psi. Remember this (underinflation) is how the whole Ford/Firestone problem started. To me an overinflated tire makes the ride seem "harsh", not bouncy. Not ENOUGH bounce at 35 to 40.
"This is not the true qualities"

Gilly