Small Engines (Lawn Mowers, etc.): snowmobile track drivers, roll pins, track drivers

Question
are the drivers just pressed on ?

Answer
Depends on the snowmobile.  Some are pressed on and the shaft and drive cogs have to be replaced as an assembly.  Others have roll pins or bolts that hold them in place on the shaft.  You will have to visually inspect to determine which is the case with your machine.  A dealer can also tell you based on the parts breakdown of the assembly.  Hope this helps.