Little play in my rear driveline

[xhootiehoox]

In neutral I have a little slop in my rear driveline could that be a bad pinion gear or just not right I tried to go backwards in reverse and it felt like my rear brakes were locked up the hole ass end sunk down idk what's goin on truck is turning into a nightmare lol the motor swap would not have anything to do with that am I right unless some how the cluch is acting up but it drives fine forward