I think you can buy the whole syncro assy as a unit,you have to pull the tranny to get to it ,remove the tail housing ,the speedogear,the 5th&rev synchro assy and gear and then pop the top cover off, then remove the input shaft,then you can remove the mainshaft and 3,4 and 1,2 assys are accesible ,hanlon MS has a great video
which shows everything in regards to rebuilding thetrans.