It is the combined
negative air pressure inside, plus the positive pressure at the front of the trailer, which add up to create the leak IMO, and only at highway speeds. One cannot replicate this combination, except while towing under similar monsoonal conditions, unfortunately. Standing still does not cut it probably.
[ Or putting the entire rig inside a wind tunnel, of course . . . ]
A third factor occurs to me, implicit in the above, but if -- while on a two-lane road -- a big semi comes along in the other lane, the blast of air from that rig hitting the front street-side door would be huge
, and would "pump" any standing water (already pooled in the various gaps at the edges of the door) past the weather stripping IMO.
Steve, do you recall traveling any two-lane roads during your monsoonal motorcade meanderings? [ free alliteration too . . . ! ]
We all know the power of hydraulics in a variety of settings. Bulldozers come to mind -- have you ever watched them operate, and marvel at the ability of those small silver hydraulic cylinders to move the blade against such huge earthly resistance?
Good luck getting to the bottom of this. I hope Jackson Center appreciates these suggestions from the peanut gallery!