Ok I have a 2008 f150 xL , it has 200+ on it. So when I turn the truck at slow speed I hear a loud pop or bang and it feels like someone kicked the bed if my truck, I thought it was slip yoke so I took drive shaft out and re greased it , all the splines looked great , put shaft back in correctly and truck still doing the same thing, I'm not sure what it is, I heard maybe clutch packs binding up in dif, please help

 

Do you have the Trac lock/limited slip?
If so the solution unless the clutch plates are totally worn out is to add friction modifier to the diff.

If you have never see iced the fluid you may want to remove the cover and inspect and put fresh fluid in with an additional squirt of additive. Some of the gear oil already has friction modifier in it, but some people report they needed an additional squirt.

If the clutch pack is worn out fluid will not help, you'll have to Google how to inspect that to ensure its good.

Then after the diff is filled up go to a parking lot and Do a few figure 8s to work it in

 

my 07 did that too. it is the spline on the drive shaft. it is catching. not stripping but not flexing. I had to replace it. cost over $1,000 but thankfully I had extended warranty on drive train parts