replacing belt on older GE washer

The agitator on my washer has gotten sluggish, with heavy loads it doesn’t want to work at all. I removed the back cover, and sure enough the belt has gotten worn and loose. I am going to replace the belt, but the video does not look the same as my washer. The belt is above the motor. It looks like on my washer I can just undo the clamp that holds the coupling to the pump and slip the new belt through that opening. What I am wondering is if I need to loosen the motor in order to (1) get the new belt on and (2) tighten the belt. I cannot tell if there is any ability of the motor to slide so that the belt would be loosened or tightened. Thanks for any help you can give me.