09 Dbl Cab 4x4 rear lift w airbag? Heavy load, leveling.

I know I have the terms wrong, but I am looking for a rear adjustable airbag for leveling the load.
Maybe I have this all wrong, but I am going to haul a fairly heavy (400 lb) motorcycle on a hitch mounted carrier. I have used it several times in the past for short trips with no problem.
I have a 1,000 mile trip planned for next month. (each way.)
Is there some type of lift or air controlled ride height adjusting device that is available?
I don't think it's good for the truck to ride with the back end sagging for 2,000 miles..
If anyone has a suggestion, I'd appreciate it.

Thanks,
Jeff

 

Have you had the rear leaf TSB performed? I would look into this before investing in an airbag system when the TSB would be performed under warranty and would only cost you your time.

I wouldn't be too concerned with hauling the Harley especially after having the TSB done.

 

i haul 2 dirtbikes roughly 525 pounds with 100 pounds of gear all over the place and i really dont sag. One time i did bottem out, but i was going close to 100 in a 45 zone. other then that i go about 300 miles on riding trips and i really dont see a problem, other then i cant burn out with them in there(even brake starting)

 

x's 2 on the TSB...

I had the TSB done on my '09, and I haul my ATV with no issues, even offroad...

 

Take a look at Firestone Ride-Rite air bags, http://www.fsip.com/riderite/ . Easy to install and reasonable priced. I tried Air-Lift, the placement of the bag is not idea for really heavy load (1000lbs) in truck bed.