When I look at "Identifying Muncie 4 Speeds II" info, I don't see "10 Tooth and 2 rings" for the input shaft and "27 Tooth output shaft" combined together under "Input Shaft Tooth and Spline Count Related to Year" section. What am I missing here? I've counted the output shaft 3 or 4 times and I come up with 27 Tooth. Am I interpreting the ID info incorectly? Is the Tooth count different than Spline Count? I have this trany on a work bench so it's easy to see all identifying info and get the tooth count.
Any additional help with ID, Vin or what vehicle you may think this came out of originally would also be great. It was in my 69' when I got it but the VIN on the trans does not match my VIN.
When I look at "Identifying Muncie 4 Speeds II" info, I don't see "10 Tooth and 2 rings" for the input shaft and "27 Tooth output shaft" combined together under "Input Shaft Tooth and Spline Count Related to Year" section. What am I missing here? I've counted the output shaft 3 or 4 times and I come up with 27 Tooth. Am I interpreting the ID info incorectly? Is the Tooth count different than Spline Count? I have this trany on a work bench so it's easy to see all identifying info and get the tooth count.
Any additional help with ID, Vin or what vehicle you may think this came out of originally would also be great. It was in my 69' when I got it but the VIN on the trans does not match my VIN.
Brian. Don't know what site you're looking at "Identifying Muncie 4 Speeds II" but I show the 66-70 M20 with a 10-spline (not 10-tooth) and 2-ring input shaft - http://chevellestuff.com/qd/muncie.htm. The 10-spline unit should have a 21-tooth count.
This photo is to show the M20/M21 vs M22 gear cut angle but these are the 'tooth count' referred to.
The input shaft spline.
Transmission appears to have been installed on a 1969 (9) Baltimore-built (B) Chevelle (sequence starting with 300001) and 366327 is late March - last GM reported sequence for March at Baltimore was 367113. :thumbsup:
Thanks for the link. The info I had on file was from May of 03'. Must have been some bad info. Reading the info available at the link you supplied clarified my concerns.
M-22 production started in 1965 NOT 1967
1965-1970 M-22 used 10 spline inputs
1970 LS-6 and 1971-74 M-22 used 26 spline inputs
CASTING NUMBERS
3839606 main case was NOT used in 1963...
Early 1964 only
3846429 thin rib tail housing was NOT used in 1963...
Early 1964 only
9779246 tail housing was used 1964-68 in Pontiacs & Olds
3846429 regular rib tail housing was used 1964 thru the end of the 1970 model year...
All the dates are model year, because Muncie are date as model year, NOT calender year like blocks, heads, exhaust manifolds, ect...
This same mis-information is on almost every Muncie web page I've seen, which leads me to believe a lot of people cut and paste without checking the accuracy of the information...
As some of your information seems to be in conflict with them (and all I wish to know is what's correct, not who's correct), please excuse me if I ask a few questions.
Since the M22 was introduced in 1965, what main case casting was used for 1965 since you indicate 3885010 was used in 1966-67 only?
Approximately when in 1970 did the 10 spline input get replaced with the 26 spline input since both are stated for 1970? Or was the 10 spline input used with all non-LS6 1970 Chevelles and the 26 spline used only with LS6 1970 Chevelles?
What main case casting and tail housing casting was used in 1963 if not 3846429?
I think the date issue is described correctly in the paragraph
In 1967 and 1968, the date code got a year designator and a letter designator for the month such as P8A01, meaning 1968 (8), January (A) 1st (01). Note that a Muncie dated with a September to December build date was actually built the prior calendar year. An example would be the date code P8T13, meaning 1968 (8), December (T), 13th. The transmission was assembled December 13, 1967 for the 1968 model year.
This is meant to explain the year designation in a date code is the model year, not the calendar year - emphasis added here for clarity.
Do you have a suggestion for a better way to describe it?
As always, input and corrections are welcomed. I'm not a Muncie guru or specialist by any means and (generally) take other sites at their word unless I know it from other research to be false. I doubt if there are any "official" GM or Muncie documents on things like casting numbers and data are arrived at through years of looking at original stuff and I trust experts in areas like this for correct information.
This (http://www.5speeds.com/muncie2.htm) web site is where I was getting my original info too, which was a bit confusing. Part of my problem was confusing the input and output shafts "visible" tooth count vs the spline count inside the trans not visible unless I open up the trans.
Thanks for the continued discussion to clarify any other discrepincies.
Over the years I have seen a few 1970 Muncies with 26 spline inputs. I do remember that one was an M22 and one was an M21. But I can't say for sure if they were original or not. And I don't remember the partial VINs.
Colvin's books are good - but I have found minor discrepancies over the years. I can't say for sure if his Muncie information is all correct or not. But he also shows the 3851325 case in 1965.
Thanks, Byron. The 3851325 casting is shown for 63-65 for the M20 & M21 but for the M22 the Camaro.org site shows "removed." And therein lies the question, what was the casting for a 65 M22 if the 66-67 were different? I realize the thread was started with M20 questions but it was pointed out the M22 data is incorrect and that's what I'm trying to verify.
Camaros.org also notes the 70 M22 with casting 3925661 was used with a 10 spline input shaft and an asterisk note that, "Colvin reports that 454 Chevelle M22 in 1970 used the 1971-74 splines." Looking at Colvin's book, it states on page 237, "The second change was the addition of a fine-spline output shaft for Chevelle M22 applications. (All other transmission assemblies used a course [should be coarse] spline output shaft.) This dictated the use of a new extension housing, which was specific to the Chevelle M22 applications for the 1970 model year." The section goes on to say, "The 1971 model year marked the last of the major changes to the Muncie 4-speed. On all transmissions the input and output shafts were changed from coarse spline to fine spline."
Nothing is said about the input shaft being 10 or 26 spline in 1970, only the output shaft. In Camaro.org's defense I assume the M22 was a 454-only option so why bother to list it twice - once for 1970 with a 10 spline input shaft and a second time for 1971-1974 with a 26 spline input shaft and both with the same maincast number of 3925661?
In Colvin's table of the M22 (page 246) the maincase is still listed at #3925661 and the same main case for M20 & M21 as well on camaros.org.
Dale, since this was not directly related to the original post, I sent you a PM.
What CRG means by "removed" is better explained by Colvin. In 1965 the M22 case used was a 3851325 case machined out to use the 1 inch cluster pin. Then the casting number was ground off - or removed.
I believe you are correct. Colvin says M22 used for Corvette only in 1967, with an unknown number produced. Part number on tag used is a rare one - 3879993.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Team Chevelle
5.1M posts
115.9K members
Since 1998
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!