"Pop!" when I back up

[Toomanyhobbies]

Recently i got 4 new Bilstein 5100s (0-2" lift), the moog 1" lift rear coils, a torsion bar crank to 1", and an ebay front end kit.

Truck sits an inch or so higher, and rides like a dream, but when I put it in reverse from park there is a fairly loud "pop" from the front end that sounds like something coming unstuck. Happens more often than not but not every time. Any ideas what this could be?

Thanks

 

[Doubeleive]

brakes, calipers, parking brake, differential, sounds can seem like they coming from one place but are actually occurring some where else.