I got a 2007 F150 with a 6" fabtech suspension lift and I got I big clunk noise in 4x4 when going from drive to reverse or when turning. As i can see it's the front diff that is knocking in the bracket when the front diff is torquing. All of the bolt for the front diff bracket are parallel with the frame so their is no bracket holding the tail of the front diff from going up and down and with the extra leverage from the drop down bracket it's very easy to go up and down. Is their an update for an extra bracket??? Or is their something that I did wrong??? Anybody else got this problem??? I am about to do a custom bracket to go from the tail of the diff to the lower crossmember if I don't find anything. Any help will be appreciate!!! Thanks

 

Not sure if this is your problem because you're saying bracket but a lot of times the driveshaft will hit on the sway bay if the sway bar drops aren't put on the correct way because they are side and offset specific and if not put on properly the driveshaft will hit when engaged.

 

Even more common would be installing the drop the correct way and installing the driveshaft backwards. Lay under your truck and check to see if your front driveshaft boot is closer to the front differential or closer to the transfer case. I know I made this mistake. You will want to have the boot closer to the transfer case.

P.S. Take some pictures maybe and let me see.... if I can see what you are talking about I may be able to help out just a little bit more.

 

I have check my driveshaft and it's install correctly with the slip yoke at the transfer case. But the sway bar seem very close to the bar that goes from the rear crossmember to the transmission crossmember maybe my drop bracket for the sway bar are not install correctly. They angle going backward??? Thanks for the help!!!

 

When under load, my front diff also raises and lowers. It's odd, but looks to be designed that way. Email Fabtech and let us know what you hear. I actually have a video of it somewhere, let me look around. Unfortunately PUTFILE deleted the sumbish.

 

A friend of mine installed a lift on his Chev truck and had to grind the diff case on the edge for clearance