Datto knocking noise when reversing

[padey]

My GTR makes a knocking noise when reversing. The more load, ie reversing up a hill, the louder it gets.

Is it my rear diff or gearbox? Sounds like it's coming from the back end.

[Swill]

Check the bolts on the gearbox cross member maybe?

[Chase Rockwell]

Its the halfshaft uni's

[GTSBoy]

Could well be CV joints.