Standard Transmissions

Muncie M20, M21, M22, and other standard transmission. This page will help you calculate what the gear ratios are for your standard transmission. It can be used for any type of transmission including 3 speed and 5 or 6 speeds. As long as you can see the gears through the inspection cover or have the parts on a bench and can count the teeth for each gear you can calculate the ratios.

You can print out a gear ratio worksheet for any transmission by clicking here

Click on the diagram to see larger sample of our M20 calculations

EXAMPLE GM 1965 Muncie M22:

Count the main teeth on the pilot gear - 24 and divide by the main teeth on the countershaft - 29 = .82758
Count the teeth on the mainshaft and the countershaft and divide large number by the small number to get ratios for each gear set.

1st - 36-17 = 2.1176
2nd - 30-19 = 1.5789
3rd - 27-22 = 1.2272
4th - 1-1

Then divide by the pilot gear ratio of .82758 by the countershaft ratios

1st gear - 2.117 divided by .8275 = 2.558
2nd gear - 1.578 divided by .8275 = 1.9079
3rd gear - 1.227 divided by .8275 =1.4829
4th gear 1-1

Round out the decimals
1 : 2.56
1 : 1.91
1 : 1.48
1 : 1