I had the transmission rebuilt with a lot of new parts summer of 2020 and now it is stuck in 4th gear. Since 2020 I just tried to not use 4th for extended time as that was what seemed to cause it to stick. I was always able to take gear shift cover off and use a crowbar and leverage the fork back into neutral but not this time.... also have always had it pop out of 2nd when going downhill. 2nd and 4th are the bottom left and right respectively on the H pattern of the shift. Any ideas on what will not allow the fork to budge? I have tried on level concrete with the clutch in, with the 4 wheel drive in and out, with the high/low in and out....