Hello, i have been doing some digging on a muncie and haven't come up with a sure answer as to what I got. There is no leter stamping after the part number to indicate a 20, 21, or 22 I know the 3925660 casting was used for all three types. the side cover indactes <TABLE cellSpacing=4 cellPadding=4 width="90%" align=center bgColor=#cccccc border=0><TBODY><TR><TD>[FONT=Arial, Helvetica, sans-serif]3884685[/FONT]</TD><TD>[FONT=Arial, Helvetica, sans-serif]Cover issued with "584" tail stud type shift shafts[/FONT]</TD></TR></TBODY></TABLE> the tail end indicates <TABLE cellSpacing=4 cellPadding=4 align=center bgColor=#cccccc border=0><TBODY><TR><TD>[FONT=Arial, Helvetica, sans-serif]3846429[/FONT]</TD><TD>[FONT=Arial, Helvetica, sans-serif]1963-1965 Regular thick web, driver speedo, 27 spline[/FONT]</TD></TR></TBODY></TABLE> part # P8H28 (Oct. 28,1968) Vin # 28P355895 Casing # 3925660 Sidecover # 3884685 Tailend # 3846429 Bellhousing # 464697 The vin number comes up non existent so any help identifying this before i buy this would be any help. The owner insists this is a m22 but I need a little help. Thanks!
Pop the side cover off...if it has straight cut gears, its an M22. Every Muncie for sale is an "M-22 Rockcrusher", just like every car has a "Corvette engine"! This might help: http://www.nastyz28.com/chevy-manual-transmission-identification.php
The guy wont pop off the cover for a picture, I'm in California and he's in the east cost. All I have is the numbers he provided. I was hoping someone could help me with the vin #
I would say "buyer beware" with that one then. What trans it is aside, any seller should be willing to do that.
Most M-22s have a large output shaft and fine spline input shaft with no rings cut around the out side of the input.If it has a large output and either 2 rings or 1 ring on the input it is a heavy duty M-21 FROM A 71-74 GM car.The small output M-22s were either fine or co**** inputs withe no rings on the inputs.
TAKE A LOOK AT THE CLUSTER PIN SIZE 7/8 PIN IS A M20...1" pin is a m21 or m22, then if it has straight cut gears you got a m22,if the pictures are your trans it's a m21,, man
Thanks Larry, not my trans. I was going to buy it as a advertised m22. But it looks like 20 or 21 gears to me but i'm not a pro.
This may help FIRST DESIGN MUNCIE The first design was from 1963 to 1967 and is considered the weakest of the bunch. The cluster shaft is 3/4 inch dia., the selector plate has an internally pressed stud. Input shaft is 10-spline and selector shafts are outfitted with 5/16th inch studs. Example: Typical date code0503N P-muncie 05-May 03-Third day. D/N-Day or night shift(not always coded) There is no year designation on these transmissions. MONTH 01-January 02-February 03-March 04-April 05-May 06-June 07-July 08-August 09-September 10-October 11-November 12-December THE SECOND DESIGN The second design muncie (1967-1968) increased the cluster shaft diameter 7/8ths inch and included the second design selector(side) cover with the larger diameter pin externally pressed in to prevent it from shaking loose from the case. Selector shafts studs increased to 3/8ths inch. The 10-spline input shaft remained. Typical date code: P7T02 P-muncie 7-1967 T-December 02-second day MONTH: A-Jan. B-Feb. C-Mar. D-April E-May H-June K-July M-Aug. P-Sept. R-Oct. S-Nov. T-Dec. THE THIRD DESIGN(1968-1973) Due to an increasing number of selector shafts breaking off, the only change made in 1969 was to alter the selector shafts by drilling and tapping them to accept a 3/8ths bolt instead of studded shaft accepting a nut. Subsequent component changes made in 1970 changed the input shaft to a 26-spline(fine) and increased output shaft diameter to accept a T-400 trans. yoke. The final incarnation of the muncie lasted until 1973 when the transmission was taken out of service. 1969-1973 Typical date code: P9B08C P-muncie 9-1969 B-February 08-Eighth day C-M22 MODEL IDENTIFICATION(1969-1972) A-M20 B-M21 C-M22 Note: not always stamped Originally, identifying the transmissions by external markings was simple. The M20(wide ratio) trans. had two grooves cut into the 10-spline input shaft and no fill plug in the case, while the M21(close ratio) had a single groove on the 10-spline input shaft and no fill plug on the case. The M22 had no grooves on the input shaft and was the only transmission to be equipped with a drain and fill plug. Unfortunately, over the years, replacement cases and gears offered by Chevrolet and aftermarket manufacturers did not follow the G.M. ***embly line identification system, so trying to use this method to identify a transmission is almost impossible. To determine close ratio(2.20:1 first gear) or wide ratio(2.54:1 first gear), mark the input shaft and output shaft, engage first gear and spin the input shaft and count how many revolutions the input shaft turns to make one revolution with the output shaft. Just less than 2 1/4 turns is a close ratio, and a little more than 2 1/2 turns is a wide ratio. M22 transmissions can only be identified removing the selector cover(side cover) and visually identifying the straight cut gears-all other muncie transmissions had conical cut(angle) gears. The most well known Muncie transmissions are the M20(wide ratio), M21(close ratio), and the M22(rock crusher). Although not mentioned much, there was also an M23 transmission that was used, beginning in 1970. The M23 is recognized by a 26-spline(fine) input shaft and a large output shaft that requires a T-400 driveshaft yoke. Although some claim that the M23 is a 'rock crusher', it is indicated that this box was ***embled in both wide and close ratio components and also with straight cut gears common to the rock crusher (M22) transmission.
The Jalopy Journal
