Dale,
We all probably have the same problem, the venting is just not big enough to handle the pressure and volume at the truckstops. Remember, the trucks don't have a dinky little 2" fuel spout, the saddle tanks have BIG openings, anywhere from 3 to 6 inches and vent while filling.

If it's quiet enough while fueling (a rare occasion) you can hear the rush of fuel as it gets full and then cut back the flow. I try to use the RV side at Flying J with the lower pressure pumps, just so I don't have to change shoes to get back in the bus. The big truck side is always bathed in fuel and oil and you can trash your carpet pretty quick. It takes a little longer to fuel, but we're not suppose to be in a hurry.