This is useless with out something in it.What are you talking about ?? Mine is tight against valance panel and if it hits so does the exhaust. You get in that tight of a place it is no place for Passport The receiver has nothing to do with what hits with a trailer, the height of the ball is the same no matter where the receiver is. OEM just takes a bigger drop.....
When you put something like this on it sticks out the back of the vehicle.
When you go over a dip, this can hit the ground if the dip is big/deep enough. The back end of the rack will hit the ground first.
This too sticks out of the back of the vehicle. Possibley not as far, but it sticks out.
When you couple A to B then C become a pivot point.
When you take the combination of A & B over something like this.
A & B pivot at C. If A is lower than B then it pivots down at C. Depending on the angle of the slope the underside of C can and does strike the ground at the bottom o the pivot point C. I know, the in-laws do it with their trailer when they back in or leave and so have I. When B is on a downward angle it also puts more weight on A forcing the back of the towing vehicle down a bit. The amount depends on the weight and angle.
If you install the hitch that is 2" lower than the OEM, then there is greater chance for the pivot point to hit the ground when towing a trailer in such situations.