Yeah, pulling in the clutch was the only way to push it around to load it back up in the truck. Same symptoms, but not 100% sure what your bike is doing. No matter what you will have to drain oil, pull the clutches and basket. The shift mechanism is right there behind the basket. There is the deal that the shifter pushes into the drum, and the drum itself that clicks into gear then returns to its original position. If that slider deal sticks to the drum and doesn't spring back or the drum doesn't complete the shift then it will act that way. I think its even possible to mess with it while leaving the basket in there. My similar issue happened on my 250 which has the inspection cover for the clutch. I bet the cases will not have to be split. Get her up on a stand and get into it. Make sure the little spring on top of the mechanism in there is pulling the slider back to its original position. The other spring on bottom, is the one you still feel.
I'm no mechanic either. I just wear-out parts, then I get on here, and figure out what I did, then what I need to do. Maybe someone else can chime in here and give better detail, and actually know what all of the parts that I'm describing are called.