MUNCIE Input and Counter gear
Tooth Count
MUNCIE MODEL/YEAR MAIN DRIVE GEAR (TEETH) COUNTER GEAR (TEETH)
M20 1963-65 Wide Ratio 24 17-19-22-29
M20 1966-74 Wide Ratio 21 17-19-22-25
M21 1963-74Close Ratio 26 17-19-22-27
M22 1965-74 26 17-17-22-27
Main Case Casting Information
3831704 1963- 207 three speed front bearing, patent pending, 7/8"countershaft
3839606 1963 - 1964 standard bearing patent pending, 7/8" countershaft
3864 1964  7/8" countershaft patent pending
3851325 1964 -1965 7/8" countershaft patent pending 1964
3851325 1964 –1965 7/8" countershaft patent number
3885010 1966 -1967 1" countershaft patent number
3925660 1968 – 1970 1" countershaft patent number
3925661 1970 – 1974 1" countershaft patent number
Extension Housing
3831731 1963 thin Fin driver speedo 27 spline
3846429 1963 thin Fin driver speedo 27 spline
3846429 1963-1965 thick web, driver speedo, 27 spline
9779246 64/65 long tail driver speedo 27 Spline
3857584 1966 – 1970 passenger side speedo, 27 spline
3978764 1970 – 1974 passenger speedo, 32 spline output
Side Cover Casting Numbers
3831707 1963-1965 Early side cover stud type shift shafts
3884685 Cover issued with "584" tail stud type shift shafts
3950306 Short boss with bolt on type shift shafts - no switches
3952642 Long boss bolt on type w/ TCS switch on 3-4
3952648 Short boss bolt on type w/ TCS switch on 3-4
335308 Long boss bolt on type with neutral safety switch. Some have
a boss for the switch that is cast but not machined on 1-2.

Month Code Chart

 Letter: A January        Letter: E May          Letter: P September

 Letter: B February      Letter: H June          Letter: R October

 Letter: C March          Letter: K July          Letter: S November

 Letter: D April            Letter: M August     Letter: T December