My 1st 68 panel

[richard2717]

One question, I have been told it has a Muncie 4speed. How do I determine exactly what it is? It is definately a 4 speed and not a granny top loader, but I had a 4 speed in my old 69 chevy that I ended up pulling out in favor of the 3 speed it originally had because the 4 speed was so closely geared. I was told that one was a Saginaw but I don't know the difference in them. I have always been told I should be looking for a "Rock Crusher" Muncie, which I assume would be the M21, but I don't know how to identify it.

Richard

[406 Q-ship]

Originally Posted by richard2717

One question, I have been told it has a Muncie 4speed. How do I determine exactly what it is? It is definately a 4 speed and not a granny top loader, but I had a 4 speed in my old 69 chevy that I ended up pulling out in favor of the 3 speed it originally had because the 4 speed was so closely geared. I was told that one was a Saginaw but I don't know the difference in them. I have always been told I should be looking for a "Rock Crusher" Muncie, which I assume would be the M21, but I don't know how to identify it.

Richard

Muncies are all aluminum cased, saginaws have cast iron cases. M21 is not the "rock crusher", that would be the M22 with straighter cut gears (they are much noiser than any of the other muncies) The M21 and M22 have the same gear ratios inside and are close ratio (2.20 first gear), they typically need a shorter rear axle ratio to work well (3.73 at least in a car). There is an M20 as well that is the wide ratio version of the muncie (2.52 first gear). The only way to truely tell which muncie one has is to pull the side cover (for the M21 and M22 ID) or to count the 1st gear ratio to tell a M20 from the M21 or M22.

It is easy to get the Borg-Warner T10 mixed up with the Muncie too. T10 have the reverse gear inside the main trans case, where as the Muncie is in the tail housing.