Hello . Im Bobby
I have worked on many 1086 tractors, The shifting has always been a problem. There is no kit that I know of to make it shift easyer, We use to weld the shifter links onto the spline shifter tubes to take out slop. and also make sure all the joints are tight.
Also make sure you clutch toe play, transmission brake, and TA dump valve is adjusted correctly.
Hope this helps, your can reply back if you have any questions.