[gfmoto]

Ok, I'll try at some point to get a video but in other attempts the sound doesn't come out clear on the video.  So I'll do my best in a verbal description.

Noticed it when running high gear before, now noticing it in low.
When going down bumpy or rocky hill hearing a "clunking" noise and can feel it in the floor under your feet.  As if the feeling or sound of a loose transmission in say a jeep. Feel it in the floor boards as you would if a small rock hits the skid plate.
Doesn't do it when climbing up a hill or when on flat surfaces or when the engine is doing any kind of pull. Even worse if I let it just coast down a bumpy hill. 

Tried to replicate it with engine off and rocking it forward and back but nothing, nothing seems "loose".  Think I'm going to pull the skid plate and get a closer look.
Or do I have to pull the interior plastic out and check ? 

[NMKawierider]

Sounds like a front driveline problem. Maybe a bad carrier bearing or U-joint or like mine, very loose spline....except mine does it's thing which is like a whipping driveline under load, not costing. Either way is tough enough..IMO to get to it.

[Cosmosdan]

I get the clunking from the rear shaft. Mine is pretty sloppy.

[gfmoto]

Sounds more rear, but feeling it in the floor concerns me.

[NMKawierider]

Check the motor mounts...CFM is known for loose bolts...and broken mounting tabs.