1969 Muncie transmission identification
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1969 Muncie transmission identification
Trying to ID the trans (M21, M22, etc...). Vertically on the side of the trans is the date code P8K12 (not P9K12, even though it's a 1969 car) and the other set of numbers after the 19S match my VIN. It has no suffix (A, B, or C) after the P8K12, but it seems suffixes were used after October 1968, so the lack of the suffix seems to make sense (the P8K12 code makes a July 12th date if my research is correct). Are there other codes on the trans to help ID the trans type?
Edit - By the way, I dropped the tank, hoping the tank sticker would ID the trans type, but the sticker was nowhere to be found.
Edit - By the way, I dropped the tank, hoping the tank sticker would ID the trans type, but the sticker was nowhere to be found.
Burning Brakes
Joined: Jan 2009
Posts: 1,224
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From: Clarksville Indiana
I just went through all this with mine, this should tell you everything..
http://www.5speeds.com/casting.html
http://www.5speeds.com/muncie2.htm
http://www.5speeds.com/casting.html
http://www.5speeds.com/muncie2.htm
Former Vendor
Joined: Jan 2009
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From: League City Texas
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St. Jude Donor '11-'12, '14
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I just went through all this with mine, this should tell you everything..
http://www.5speeds.com/casting.html
http://www.5speeds.com/muncie2.htm
http://www.5speeds.com/casting.html
http://www.5speeds.com/muncie2.htm
appreciate it. I can use those
Melting Slicks
Joined: Nov 2004
Posts: 2,672
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From: Nevada City California
The transmission main cases prior to '71 model year did not use two screw in plugs (one for filling, one for draining), if you had an M22 it would have had two plugs, so that should eliminate this choice from the three possible.
Drifting
Joined: Sep 2006
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From: MS
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Thanks all for the info.
I'll have to check for the casing codes when time frees up. I don't remember the # of drain/fill plugs it has; will have to check for that, too.
I think it is an L71 car; it's got the correct tach, console plate, HD rear, etc... but the block is incorrect and could not locate the tank sticker. I dropped the tank a few weeks ago for that but no sticker was found. Was the correct HP tank, though.
I'll have to check for the casing codes when time frees up. I don't remember the # of drain/fill plugs it has; will have to check for that, too.
I think it is an L71 car; it's got the correct tach, console plate, HD rear, etc... but the block is incorrect and could not locate the tank sticker. I dropped the tank a few weeks ago for that but no sticker was found. Was the correct HP tank, though.
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Drifting
Joined: Sep 2006
Posts: 1,259
Likes: 2
From: MS
I would ask the original poster 1996ta how early of a 69 he has. I guess it is possible the that the tranny
had an issue and was sent back to Muncie and then sent back to STL for installation in his car.
The question is would the original stamp stay or would Muncie grind it out and restamp it?
had an issue and was sent back to Muncie and then sent back to STL for installation in his car.
The question is would the original stamp stay or would Muncie grind it out and restamp it?
Safety Car
Joined: Apr 2000
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From: Wichita KS
cc
BTW, July or August would be early car of the next model year. Late cars are May, June.
Last edited by CCrane65; Feb 21, 2009 at 03:02 PM.
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From: About 1100 miles from where I call home.
Oddities are out there. I looked at the case number on my car, found off to the right from your date/VIN and horizontal, not vertical, and it's 3925661... part number listings show 660 for 68-69 and 661 for 1970 and later. However, the car is so late a 1969 car (November) it must be that fuzzy line...
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Yes, oddities are definitely out there. Fellow CF member (2-13-09 post date, 7:39pm) has the same exact issue:
http://forums.corvetteforum.com/c3-g...ssion-pic.html
http://forums.corvetteforum.com/c3-g...ssion-pic.html
Last edited by 1996ta; Feb 22, 2009 at 04:16 PM. Reason: link
Drifting
Joined: Sep 2006
Posts: 1,259
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From: MS
I think there is too much of a gap in time for this to be the original transmission.
Your tranny date is July 68 and car's build date is August of 69, and don't see
any way the tranny hung around GM for 13 months.
What does the VIN stamp on your engine look like?
The two stamps were made by the same person at the same time so both the
engine and tranny stamps should be the same.
You can also find out if it's an M20 or M21 by the drop in rpm going from 3rd to 4th.
Go on the road at exactly 2000 rpm in 4th and maintaining the same mph, downshift to 3rd.
If the revs go to about 2900, it is an M20, if they go to about 25-2600 it is an M21.
Your tranny date is July 68 and car's build date is August of 69, and don't see
any way the tranny hung around GM for 13 months.
What does the VIN stamp on your engine look like?
The two stamps were made by the same person at the same time so both the
engine and tranny stamps should be the same.
You can also find out if it's an M20 or M21 by the drop in rpm going from 3rd to 4th.
Go on the road at exactly 2000 rpm in 4th and maintaining the same mph, downshift to 3rd.
If the revs go to about 2900, it is an M20, if they go to about 25-2600 it is an M21.
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The engine was decked so has no vin stampings.
Makes no sense somebody would go through all the trouble to re-stamp a trans and not use the P9 code. Plus, there's no markings or blemishes around the trans stamps indicating a re-stamp. I'm sure it's original, just one of those things that happen, just like the guy's trans above. Not sure how it is with Chevy's, but my old GTO had the original engine/trans and the engine was coded with a 2 where a Z should've been (the trans used the Z). Things happen when humans are involved.
Thanks for the RPM drop info, that helps quite a bit
Makes no sense somebody would go through all the trouble to re-stamp a trans and not use the P9 code. Plus, there's no markings or blemishes around the trans stamps indicating a re-stamp. I'm sure it's original, just one of those things that happen, just like the guy's trans above. Not sure how it is with Chevy's, but my old GTO had the original engine/trans and the engine was coded with a 2 where a Z should've been (the trans used the Z). Things happen when humans are involved.
Thanks for the RPM drop info, that helps quite a bit
4th, 660, case, chevy, corvette, grind, identifcation, identification, m20, m22, muncie, numbers, part, tansmision, transmission, vin
