Sounds more like a clutch problem. I believe a synchronizer helps by spinning the gears at the same speed to help their meshing. Without it you need to rev the engine the same speed as the drive train is turning for a smooth shift.

However, when you are standing still, nothing should be turning. So, if you are having engagement difficulties it could be the clutch.


54 3100 with 235
62 flatbed dump C60 with 261