Jage, good point! Rumble strips are a good example to activate some noise.
Or cracks in the road that are covered with raised tar.
Try driving over those little raised reflectors,
that are positioned next to the road lines.
But try this in the daytime with no traffic!
It would be interesting to hear what other people "hear" when driving over these "urban obsticles."
I was under the van today, tried tapping stuff, no rattle.
I am concluding that the rear leaf springs are making the rattle.
I have Road Master springs back there.
They basically split the weight on either side of the axle.
This makes for better handling and towing.
Otherwise, the ride is quiet.
Thanks for the replies!