EDIT: HuskerJ has a much better answer than mine.  Do as he suggests.

It sounds like it may be a belt showing its age.  They guys that really push the limits on their machines will say a 7 year old belt is past its prime and needing replaced.  My nephew says when it comes apart it make a really bad noise and then you stop.

I hear a lot of talk (especially in Polaris groups) about clutch spring and weight kits to improve low speed engagement.  I know on my Polaris Ranger it has to get up to about 2000 to 2200 RPM to engage.  Seems awful high to an old truck driver.

One place that has been suggested for CanAm is Dalton Industries.  For a 2014 commander they recommend this kit  http://www.daltonindustries.com/product_detail.php?product_id=110.