I have 2007 Grand Caravan with a Uhaul class III hitch that scrapes the ground on hills, speed bumps, etc. I use it for my bike rack to haul bicycles. My driveway is not all that steep, but when I back down it scrapes the bottom of my driveway when everyone (2 adults, 3 small kids) is in it. When everyone is in it and bikes on the rack it scrapes going over speed bumps in the neighborhood. The back end sags too low. I cannot find any adjustable air shocks available to raise the rear up when loaded. Leaf spring helpers don't work. Anybody have any ideas to get the back end up a little? Anyone else have the same problem?

Thanks,

Chris