My 1720 has 475 hours on it. It was parked outside for 13 months not being used. Now the clutch will release the pto but not the drive clutch. Any suggestion before I have someone split the tractor into.
There are ways to try to force it loose by chaining to a tree, etc but I would hate to risk breaking something by diong so.
There's a small access port on the left side of the bellhousing used to adjust the clutch. You may be able to work things loose through it, going gently and rotating the engine to work your way around. Getting horsey can cause the releasing/friction disk to warp or crumble and then need to be replaced.
btw, If you don't have this, get it, IMO the best ~$30 investment for a 20 series. If you like I can link the page(s) for clutch adjustment/check. No need to split for any of this.
A number of people have bumped them into a tree and freed it up. Your tractor your call. Oh and make sure you push the clutch in if you do the tree bump idea.