02 Quest 650XT falls out of gear - causes?
 

I'm not sure if it's a matter of the natural fall of the shift lever, but when running in high gear, the quad will throw the gear and sometimes slips into low gear when I've slowed down.

It never slips out of low, but will arbitrarily fall out of high - almost like an RPM hole in a manual tranny car.

I'm not sure where to start looking, but am open to suggestions!