Combine the 2 posts??
Have a mod delete one.
The banging could be the clutch dog?
Possible bad adjustment?
If it continues? it could ruin the forward gear if it hasn't already.
Try unhooking the linkage and shift by hand and see if it continues.
Then? the propshaft needs to come out and the parts inspected.
The RPM's at 7800??
Try another tach? to verify the old one.