Cutch issues? 300 TRX Fourtrax

[Jman]

Hoping to get some advice on my 300 if possible. Got a '93 300 TRX Fourtrax 2wd and it has been a perfect machine. Well maintained, never abused in anyway. Recently when lifting up on shifter it will not disengage before jumping into next gear. It's as if it has no clutch action between shifts. However, the clutch doesn't seem to slip any whatsoever on take off. It accelerates as good as it ever has (or so it seems). On rare occasion, the shifting will work as it should but three or four shifts later, it's right back to the having to force it into the next gear. This performance is the same regardless of upshifting or downshifting. Basically it feels like you are just ramming it into the next gear.
It's 18 years old and I've replaced a brake cable and the rear brake shoes......that's it. Zero oil consumption! Can't speak highly enough about it.

Have any of you ever heard of this type problem? Any advice on further testing to properly indentify the exact issue? Any advice appreciated.
Thanks in advance,
Jonathan

[Here 2 help]

Several possibilities here:
Broken clutch plate - warped clutch plate - improper grade of oil - clutch plates damaged by improper type of oil - wear on the "fingers" of the clutch basket - improper clutch adjustment - broken or weak clutch spring - loose nut securing clutch to transmission shaft and a few more unusual causes.
Start with the obvious; change the oil. Use a 10W30 or 10W40 weight and be sure the oil has a JASO rating of MA or higher or an API rating of SJ or lower.