660 front drive shaft

I have a 07 660 grizzly and noticed popping noises coming from the front. It does it whether in 2 or 4 wd. The shafts going to the wheels feel tight. The left side spins smooth and easy the right side is harder to spin and is notchy feeling. I asume that is because its turning the gears from that side.? The drive shaft from the engine has play side to side when I pull on it. It seems to be more on the engine end. Is this wore out or normal?
I pulled the boot off the differential end and it was greasy and seemed tight just the yoke would rock on the shaft a little. Do I need a new shaft and how do you change it? Looks like the differential would have to come loose and slid forward to give it room to be removed. Thanks for any help you can offer