There are some CV joints on Can Ams that just refuse to come off. I even took it to heavy repair facility...bigger vises and bigger hammers...no luck. Find out from a few dealers that some just refuse to come off, even though the circlip is seated in the groove and still has some play. This was the first one I couldn't get off...ever! And I've pulled a ton apart on quads, cars, trucks...you name it.
So if you run into one, you are not alone. DON'T DESTROY YOUR JOINT IF YOU ARE ONLY REPLACING A BOOT!!! Simply remove the clamps from the inboard and knock that joint off and install the new boot from that side. You will need a needle fitting on the grease gun to repack new fresh grease in the "non-removable" joint and push out contaminants. I use universal ear style clamps from NAPA. Recent work taught me that the small ones just fit on the smaller ATV axle shafts. I also use a Lysle boot clamp tool with the built in anvil for ear style clamps, about $30. If you use stock CanAm clamps, then I use a pair of end-cutters with the sharp edge ground down VERY little just to take the sharpness away some.