when im reversing and firmly hit the brakes i get a thunk/thump noise. I
re-tightened the lift and I still have the noise. Its annoying me!!!

 

Could possibly deal with your rear rotors. Have someone sit back there and listen, track it down...that is the first step in figuring out your problem.

 

Is it coming from the rear? It could possibly be a loose backing plate for your park brake, check that out it's an easy fix.

 

its from the front end. I had my buddy help me out, and we found it to be my half shaft on the drivers side. should i be worried?

 

Your halfshaft sits right in your hub so I'm betting its your hub. Maybe your angles are extreme? Either way I'm assuming it's your driverside hub. You can get them for around $50-75 from takeoffs. Click here. I would search for them on a 2006 F-150 so you get the latest design if changed. The only other thing I can imagine it being is a tie rod, this only happens when in 4wd though right? If you can check this for me, put your truck in drive and get under there to see if the front driveshaft spins while in 2wd. Have a friend drive it slowly. The 4x4 solenoid fuse shorts out due to rainwater dripping on the solenoid under the hood, and/or condensation. Doing this will lock your hubs and may cause hub damage when used in 2wd.

 

thanks for the help, i will try this tomorrow. yeah this is the drivers side. i can move the hub back and forth (twisting) this should be under warrenty right?