Just a suggestion that I am going to pass along. The Ol' Muncie 3 speeds and 4 speed transmissions have CONE shaped synchonizers. I was told by a gentleman older than I am who worked for GM back in the late forties and fifties that these transmissions have to have 90 weight mineral based gear oil which has a higher ash content, or the synchonizers will not work properly. The new gear oil most parts houses carry in 80w 90 or 85w 140 is GL3 or GL5 rated. this gear oil is too slick which will make the synchornizers slip instead of engaging. I had the a similar problem with Muncie 3 speed in a 1958 Chevrolet Biscayne. He sent me to NAPA to get straight 90 weight mineral based gear lube. We changed the gear lube and WHAT A DIFFERENCE! You can purchase straight 90 weight mineral based gear oil at NAPA, or a farm supply store....like Tractor Supply. Old tractor that the farmers still use have to have this gear oil also.

"Pay attention to the details! It ALWAYS pays off."

1949 Chevrolet 3100 Series 1/2 ton Pickup
1964 Chevrolet C10 (Ol' Yella) (SOLD)
1958 Chevrolet Biscayne 2 door (SOLD)
1970 VW Beetle