Check the commander forums. Lots of guys are replacing them so might want to do some research and find out why. I don't think they're being used on newer models either.
Chances are if its a 2012 the shocks need to be rebuilt. Oil, or air shocks. Probably about 90% of used quads are running around on springs on top of sacked out shocks.
Oil needs to changed, seals need to be replaced. With a air shock, air is the spring so it is more noticeable to a trail rider.
There has been a lot of problems with the air shocks. Probably the reason why CanAm dropped them off the Max and XMR. Not just leaking but pump and computer problems too.