This is a repost from earlier in the day. I want to thank Bucko for his help but wanted to get additional opinions and help determining whether I can fix this myself or need to take it into the dealer. I just copied my original info.
Thanks for any help!

I need some help with a strange problem. I have a 05 screw with the 6ft bed and the bed is leaning to one side, cant tell if one side is high or the other is low. Its primarily at the rear of the bed. There are no leaks from the shocks and the leaf springs are in tact and connected. Shocks don't appear to be stuck since they are moving when I shake the truck. I haven't been in any accidents or hit any bad potholes. The truck usually just sits in the garage since my wife and i work from home. Anyone had this issue or know of a service bulletin?

I've just looked under the truck and nothing is out of place. I purchased the truck new. No accidents, no towing in 2 years and never abused when I did. Only a few cars and trailers with 8k max weight. This is a new issue. Have a bed liner so unable to see the hex bolts in the bed but there are no gaps between the bed and frame. Does anyone know how the measure the leaf springs? I don't know how the frame could have twisted (no offroad, no accidents). The truck only has 70k on it. I'm thinking one side is low. Need more help to determine possible causes.

 

Spring shackle. Look really good up inside the bed near the bumper on the side its leaning, you probably had one crack

 

I just checked and both shackles are good, no cracks, both in same alignment and both seem to be floating/free to move with the suspension. Checked U-bolts for the leaf springs and shock mounts and both are fine. Both shocks move freely. It's the weirdest looking thing and I can't figure it out. Does any know what the height should be between the tire and the edge of the fender? At least that will let me know which side is effected. I have stock size 255/70 - 17.

 

You might want to grab a tape measure and head out to a large shopping center to locate another 04 to 08...then measure their truck to get your measurements.

Looks like this is one for a suspension or body shop. I'm thinking you could take it to a Ford body shop, ask one of the techs there to look at it and offer their opinion.

I have found that a box of Krispy Kremes goes a long way!

 

Have Any pics for us?? I would like to see this...thanks

 

Well,
I was finally able to get my truck out the garage today. Garage door broke this weekend so the truck was stuck in the garage. I'm assuming it was a suspension issue. I pulled the truck out the garage and then backed it up in the driveway and the suspension settled. It was still a little cocked to one side but after 10 min, it corrected itself. Haven't had a chance to double check the suspension components again but will soon. Still can't figure out what happened.

 

Just an idea but do u always have a full tank? Could it be the gas tank being on one side? Just an idea