just gotta get a little rough with them at times i had a hard time with mine just kept beating and prying till they came off cleaned the shafts and never-seized the crap out of them and now they move effortlessly
It might be easies to try and get it apart if its not on the machine, take the panel off the back, knock out the roll pin on the shaft and if I'm thinking corectly it should slide out, but still attached to the spinner. Atleast then you can work on it in your shop and not on the machine. Just an idea......
Those couplers with the slide collars suck. We had one stick on our 2388. We tried to use brute force to get it off, but broke the internal mechanisms in the process. We ended up taking the entire shaft off like ayars660 said, then torching the coupler off. Both couplers were replaced with the newer style one that have the push button. I highly recommend them. They'll save a lot of hassle.
When we got our 2388's (used) the spinners were rusted on pretty good and had fun getting them off you have to lift the coupler and turn counterclockwise which we werent doing . But once off we took them apart and greased them up really good and now have no problems other than greasing them once in a while and wiping the dust off the shaft when re-installing the spinners after dropping straw .