I've got a 2WD 2001 F-250 P/S Super Duty that is almost bone stock. The only suspension work done is the addition of air bags which are deflated. Whenever I hit ant bumps it feels like the rear axle is gonna come up through the bed of the truck. I've changed the shocks and there's no change.

Cars and other trucks seem to take the same bumps like a Cadillac.

Any help will go towards saving my marriage since I'm building a house 1/4 mile from a R/R crossing.

 

throw some 1/2" plywood across the tracks?

seriously, new shocks (Rancho RS9000XL) really helped my '04 Sierra 3500, but you said you did replace your shocks (with what, stock Motocraft ones?).

you could try Sulastic Shackles to get a little softer ride as well

 

About 2 thousand pounds of weight in the bed ought to do the trick.

Or alternately,

If you're driving around most of the time with no load in bed, air your tires down to 50-60 psi. Just don't forget to air them back up again before you put a load on.

 

Every air bag system I've seen recommends at least 5 or 10lbs of pressure in them at all times. I also agree that lowering the air pressure in the rear tires is a great idea when not loaded.

 

Is there a lot of rust on your springs and spring mounts?

 

Did you look at your bed rails? They may be rusting bad. Typical with superdutys. Mine are getting bad. Have the same issue. I had to temporally screw a 4x4 block between the frame and bed because the front rail is gone. It helped alot. I am going to replace them when the weather gets better.