clack sound on takeoff

Hello everyone. I’m looking for suggestions as to why my 04 Outlander 400 Max now makes a "clack" sound only when initially taking off, or when quickly accelerating/decelerating, as in going over a bump or into a dip due to change in speed. I thought maybe the u-joints on the propeller shaft were worn, so I replaced them, but the clack sound is still there, otherwise the machine rides fine. Keep in mind, it’s only when starting to move, and when quickly accelerating or decelerating due to a bump or dip on the trail. Any ideas? One suggestion that I’ve had is that it may be a cv joint, but if it was that, then the clacking, which would be more of a clicking, would be continuous I would think. All the boots are fine, and no sign of any grease anywhere on the frame/wheels, etc. I did notice that the prop shaft is a LITTLE bit loose at the yoke joint. Is that normal?