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#1
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1970 M21 Service Replacement Transmission
I have a 1970 model year Service Replacement M21 (close-ratio) Transmission assembly and would like to know what it may be worth. I did find a reference to a GM service bulletin that documents how the Service Replacement Engine and Transmission assemblies are marked (see document below). My transmission is marked ?TO 38837, which according to the information below is correct for a full transmission assembly from the Muncie Transmission Plant. The case casting number is 3925661 and the date code is P0R29B (October 29, 1969, M21). This would be a perfect fit for a RAIII or RAIV car with the wrong transmission. The transmission is in my '66 GTO and drives/shifts perfectly.
Last edited by DANTIP; 05-03-2012 at 03:38 PM. Reason: More information |
#2
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Actually, it's perfectly dated for a 68 RA I or II car.
__________________
Some guys they just give up living And start dying little by little, piece by piece, Some guys come home from work and wash up, And go racin' in the street. Bruce Springsteen - Racing In The Street - 1978 |
#3
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trans
How much do you want for it I have a customers 68 ram air II car its a automatic but he is thinking of converting to a 4 speed sounds perfect for him. That would make me happy as I would get a turbo 400 for one of my 69 convertible projects
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#4
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Hobi,
If you have a 68 PQ t-400 and want to trade it for a 69 PQ t-400 for your convertible, I'd do the trade with you. I also have a 68 dated M-21. Let me know. My e-mail is listed below. thebosspontiac@hotmail.com
__________________
Some guys they just give up living And start dying little by little, piece by piece, Some guys come home from work and wash up, And go racin' in the street. Bruce Springsteen - Racing In The Street - 1978 |
#5
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travs
Thanks boss but I drove this customers car when it came in my shop it was really a nice shifting transmission I am going to just put it in my convertible as I know it works fine and dont care that its a 68 pq the circles I run in nobody knows or would care but thanks for the offer
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#6
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As I understand the way to decode a P0R29B tranny?
P = muncie, 0 is for year of car. 1970 R is month only 12 so not sure? But, say it is a replacement and fits all months. R does say Oct. 29 is day of month, B is M 21?
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Mike/Illinois Last edited by Judge273; 05-04-2012 at 09:12 AM. |
#7
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Is it stamped for what it's replacing...when it's replacing...or when it was made?
Doug
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71 SILVER AUTO JUDGE 70 RED AUTO III JUDGE 70 GOLD AUTO III JUDGE 70 SPECIAL ORDER SABLE BLACK 4SPEED III JUDGE 70 ATOLE BLUE AUTO GTO 69 C.RED 4SPEED III JUDGE 67 WHITE 4SPEED 400 VERT FIREBIRD 65 MAIZE 4SPEED TRIPOWER VERT GTO 65 TURQ. 4SPEED TRIPOWER VERT GTO WANTING A IV...... 20 other non-pontiacs which need to be thinned down so I can buy more PONTIACS |
#8
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Replacement Trans
Quote:
Dan Last edited by DANTIP; 05-04-2012 at 12:46 PM. Reason: correction |
#9
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trans
From what I have been told by oldtimers GM had a parts quota for non expected items. Expected items being collision or tolerance wear and or warranty related parts, non expected parts such as certain sheetmetal according to GM data at the time or options or other parts that were not expected to be replaced before such warranty were made as a run item just as for example a run of 1000 1969 fenders a run being a pair as the cars were still being assembeled so that would constitute enough parts fenders for 500 cars this is just a example as I do not have the data that GM had for replacement parts and of coarse that varied to according to what part of the country you lived in and what time of year it was.
The fender run for example woule more than lickly be punched with no holes for embles or cornering lite option as it could be used for a couple years and a assortment of options. |
#10
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Yep.
__________________
Please check out my YouTube channel for vintage/classic car and truck builds and shenanigans! https://www.youtube.com/watch?v=jq61KxKp1Is&t=14s |
#11
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I'm a bit confused. I thought "CC" stamp was for a counter case (i.e., what you got to replaced your busted Muncie case from the parts counter at the local Pontiac dealer).
I thought that a complete transmission assembly was marked "CT" for "counter transmission" or something like that. Scott
__________________
Please check out my YouTube channel for vintage/classic car and truck builds and shenanigans! https://www.youtube.com/watch?v=jq61KxKp1Is&t=14s |
#12
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Quote:
I attached a document in Post #1 that explains how "Service Replacement" parts/assemblies are marked according to a 1969-vintage GM Service Information Bulletin. Prior to seeing this document, I was unaware of the marking and the assigned sequence/numbering system used (This does explain why the high-dollar BBC replacement engines are all marked CE for "Chevrolet Engine" rather than what most people believe means "Counter Exchange"). This document does not explain what a "CC" marked transmission case is but it does perfectly match how my 1970 M21 is marked. I wonder whether a different marking approach was used prior to the release of the Service Bulletin mentioned? If anyone is interested in better photos of the markings, I'll find time to get some more detailed photos. Dan Last edited by DANTIP; 05-05-2012 at 09:25 AM. Reason: Poor spelling |
#13
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which side of the tail housing is the speedo on?
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#14
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my freind who sells muncies says, that sept thru october would be the previous year production. if this is correct then it would have been produced oct 1969, but information I have found seems to be contradictory in that it was only 67 68 that worked this way with date code and 69 thru 74 was different?
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Happiness is just a turbocharger away! 960 HP @ 11 psi, 9.70 at 146. Iron heads, iron stock 2 bolt block , stock crank, 9 years haven't even changed a spark plug! selling turbos and turbo related parts since 2005! |
#15
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Quote:
Scott
__________________
Please check out my YouTube channel for vintage/classic car and truck builds and shenanigans! https://www.youtube.com/watch?v=jq61KxKp1Is&t=14s |
#16
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Quote:
This is the only transmission I have heard of marked like this. I too called a well know builder and he had never heard of a Muncie marked like this. I just checked Ebay and there are three "high-value" Big-Block Chevrolet replacement blocks (1-'68, 1-'70, and 1-'71) and all of them follow the marking scheme explained in the GM service bulletin mentioned in the first post (one is item #330706370971). I have ZERO doubt this transmission is an untouched (never blasted, cleaned, messed with) original. The original owner of my car is 83 years old and told me he bought this transmission as a full transmission assembly from a GM dealer. I suspect GM provided vastly more replacement engines than transmissions and most builders have never seen/noticed one. |
#17
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so is it driver or passenger side?
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#18
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Muncie
The speedo is on the driver's side. I assume the Muncie plant would be told which tail shaft to use/install before shipment.
Dan |
#19
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Service Replacement transmission
Quote:
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#20
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I have a '661' case service-replacement M21 transmission stamped ' CCO 45571'. It has pass side speedo.I dont know what it was originally intended to service.
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