Reading this post made me think abour what i did to my 46 way back, 1&r were missing teeth, and I couldn't find any gears, i found a later model trans missing the input shaft and the gears looked much the same ---except the cluster had 1 less tooth ---i put it together anyway, it didn't make noise, and survived side steeping the clutch downshifts many times ---the countershaft bearings were all loose needles, not the caged ones the original trans had, I remember doing something to the thrust washers too ---I never found out what the trans was from, but the case was much different than the 46, and looked different than the 49-50 flathead trans pictures