There is also a good chance it is the slip yoke in the rear drive shaft binding, this can cause quite a loud bang from the rear end under the circumstances you describe.
Simple fix, four bolts to detach the driveshaft from the rear diff, pull the splined section apart clean and re-grease. Just need to remember to mark the two halves so they go back in the same alignment and to remove the grease nipple to release the suction or you will never get the two halves apart.
@
mtbtim
(Tim the Toolman) has a video on the fix
Slip Yoke Binding Fix
Gary