[RedDevil]

So what? I know what I feel. I understand how it works.
Don't confuse statistics with proof.
A sample of 1 is adequate to prove a point, when it is not about a single value but a functional situation.

But I've driven many other 4x4's since and notice the effect every time, and I can tell whether a car has FWD, RWD or 4WD by just driving it over a bump.
And if you recognize how it works you can do that too.

It has nothing to do with unsprung weight.
It is not about how much the car moves up and down.

it is about how much or little the car jerks backward and forward when going over a bump.
2WD: - a big jerk when the driven wheels go over the bump, none when the others go over the bump
4WD - two smaller jerks for each set of wheels.

You'd hear the revs change when the driven wheels go over a bump too, especially with a stick shift.