Backstory - I converted my 2010 KX450F into a snow bike many years ago. It has run well and has been serviced regularly. Last weekend I was out for a ride and it ran awesome for 2+ hours. Then I heard a "glunk" and was unable to shift. Bike has a Rekluse and I suspect was the only reason the bike was still running or was able to run still. A good friend towed me back to civilization. I pulled the clutch cover off, removed the clutch basket, and can access the shift rod assembly and associated gears, etc (see picture). I see nothing broken. The primary drive can spin freely with the chain removed.

Problem/question - The shifting still seems odd though it does move up and down and "click." But I can't make out if it's actually shifting or not. Can someone advise on the positioning of the (pardon incorrect name about to be used) ratchet shifting mechanism? Also, I am curious if others have seen this issue and if they could share their experiences or speculate what my root cause may be.