I got a knocking from the rear end…help

Hello guys its the Noob again...this weekend I took off my back wheels to paint the leaf springs and clean up some other things ....I drained my transmission and replaced the filter ..it has enough fluid in it ...So now my rear end has a knocking sound ....It sounds like someone is hammering something under there:angry7:...I have know idea what going on under there....should i check my gear fluid ..? please help its driving me crazy..:@:
Author: admin