Chainsaws

I have a fairly new Husqvarna 395xp; about 1 year old and not a lot of use. I was tightening the bar nuts onto the stud bolts yesterday and the rear stud bolt began to turn. I cannot remove the bar nut on the rear stud bolt now as the bolt just turns with the nut. I am sure I can drill a shallow hole and use a thread tap in the hole to apply counter torque to remove the nut. My question is: how difficult is it to replace the stud bolt. From what I can see it entails splitting the crank shaft housing to get at the end of the bolt. Is this correct? Is it something I can do or does it require a trip to a repair shop?