I recently picked up a 77 low rider fxe Shovelhead from my father as my first bike. I have never worked on any motorcycle before and am looking to learn. Once I picked it up I learned it was stuck in second gear and would not shift using the foot shifter. We were able to move it since the chain had been taken off before I got there. I have since taken the transmission completely out to look at the gearbox and figure out the problem. Now my main question is, when looking inside the trapdoor in this transmission (4 speed) where the shifting forks rest on top of two countershafts which mate on their left or right to, I assume, put the motorcycle in gear. Well, moving either countershaft independently to mate with the main shaft gear locks up the transmission. Is this supposed to happen? I have heard of engaging both to lock the transmission but this is locking with only one. Please help. Note: the transmission is still out and disassembled as we are trying to solve this.