mainshaft
 

I am having my nv4500 rebuilt, I bought the 5th gear retainer looks promising but I still have heard failures, if this does fail I will obviously get the torqueking mainshaft. I was wanting to know how hard it is to change over all the gears and to put mainshaft in?

Just a note, when you put the 5th gear on, it's gotta be snug on the splines, and then the upgraded nut usually works well (with lots of permanent strength loctite), However, if the splines are loose and the shaft doesn't properly support the gear, nothing will work well for long. As to how hard the the shaft is to replace, I'm not quite sure... if you do it before me, let me know.