kbuhagiar

Hello, folks,

I'm trying to verify the lineage of the non-original Muncie from my 63 convertible.

Case stamp (right side): P9H01A
Case stamp (left side): 319Z(or maybe a 7?)359070

Casting numbers:
Case - 3925660 - 10 - 5
Tailshaft - 3857584 GM (speedometer cable outlet is on right side)
Side cover - GM 3952648
Bearing retainer - GM16 3915020

I have decoded it to be a Muncie M-20, built on June 1, 1969 - does this seem correct?

Any idea what vehicle it came out of?

Any and all information is greatly appreciated; thanks in advance!

DZVette

Ken

I'll take a shot at it based on what I can find in Colvin's Corvette by the Numbers.

The main case (3925660) is for an M20 (wide) M21 (close) or M22 close ratio. Same for the Extension Housing (3857584).

The side cover (3952648) looks to be from a 70 or later.

If I have it correct, the P9H01A translates as"
P = Muncie 4-speed
9 = 1969
H = June
01 - June 1st
A = M20 with 2.52 1st gear

Don't know what the 319Z is.
Looks like it at least has Corvette pedigree!

DZ

RoadKing96

with everything with a few additions......I believe DZ's dating / identifiying is spot on.

Case - 3925660 Years: 1968 - 1970 1" Bore Patent Number
Ratios: M20 - 2.52 1st
M21 & M22 - 2.20 1st

Tailshaft - 3857584 1966 – 1970 Passenger side speedo, 27 spline


Side cover - 3952648 Short boss bolt on type w/ TCS switch on 3-4

I believe the 'P' means it is a Corvette breed Muncie.

DZAUTO

I thought I had covered this issue here before, but maybe not.
So I'll do it again and try to be VERY clear on it.
The P at the beginning of all STAMPED Muncie date codes DOES NOT exactly mean "Muncie". It does, but then it doesn't. The P means Passenger Muncie (as opposed to truck Muncie). Thus, all Muncie 4sp trannys in GM passenger cars have a date code that begins with a P.

OK, so does the stamped date code on a truck Muncie begin with T? Nope! It starts with an N.
Does a truck Muncie looke like a pass car Muncie? Nope, not even close. It looks like a big truck tranny.

piper

http://www.nastyz28.com/chevy-manual...tification.php

http://www3.sympatico.ca/atkinsom/history.html

JohnZ

It's out of an Olds 4-4-2 built at Fremont, California.

DZAUTO

John,
I see everything indicating it came from an Olds and built at Fremont.
But what indicates it specifically came from a 442, as opposed to another Olds model or just a Cutlass?

RoadKing96

John,
What special decoder ring do you and DZAUTO have that gives so much more descript information? What letter/numbers gave you the Olds in Fremont CA hint?

Is this something you can share with the rest of us in a more complete form. In other words....the complete list of letters/numbers that indicate who, when, where etc....

If not could you PM this info to me.

I was taking my information from a gentleman who I know has some in sight. He writes

"Serial numbers for Muncie 4 speeds always begin with the letter "P". P stands for Muncie Plant. Not for passenger car as some self proclaimed specialists may think. The letter M was used to ID the Muncie plant for the Muncie 3 speed, so P was the next logical letter. The letter O would add confusion since it resembles zero."

Thanks in Advance,
David

DZAUTO

David,
First of all, the P is NOT part of the serial number, it's part of the stamped date code for the assembly of the tranny (when the tranny was assembled at the TRANNY plant).

Where did I get the P? Or the N? STRAIGHT out of an older Chevrolet parts catalog---------------which lists the letter code for various GM trannys (Saginaw 3sp, pass car Muncie, truck Muncie, PG, TG, etc, etc, etc).

At the beginning of the stamped VIN on a tranny, there is a number which indicates which car line the tranny was installed into (at the VEHICLE assembly plant). For Chevys the number is 1, 2 for Pont, 3 for Olds, etc. The VIN on the Muncie in question begins with a 3, thus, an Olds. There is a letter in the VIN which also indicates the assembly plant. Many GM plants have long been shut down since these cars were built, therefore some of the letters used in the stamped VIN are no longer in use (and over the years, the letters for assembly plants has changed). Just before the letter in the stamped VIN, there is a number which indicates the year model of the car the tranny was installed. The one above has a 9, for 1969, which corrosponds to the 9 in the stamped assembly code. Therefore, it has TWO stamped codes indicating the tranny was in a 1969 automobile. The last 6 numbers of a VIN will be the sequence of assembly of that model car. Now, it is possible (or PROBABLE) that this numbering sequence is what indicated to JohnZ that the tranny came from a 442, or, maybe it was the 1 after the 3. And that is my question to John. I know how to tell it came from an Olds, but I do not know how to tell it came from a 442!!!

Oh ya, since I got the P as and indicator of Passenger Muncie straight from a Chevrolet publication, I think I will continue to accept that as correct information.

ctjackster

not to get you all riled up, but the use of P just ended up correlating to Munices installed in passenger cars, they didn't use "T" to mean Muncies installed in Trucks, right? (answer - no, they used M and N for Muncies installed in Trucks). "P" was just where they were in the alphabet, they did not "stand" for the first letter of the application.

Here is the sequence: M = Muncie 3-speed truck; N = Muncie 4-spd truck; P = Muncie 4-spd Chevrolet, Chevelle, Chevy II and Corvette (they skipped "O" because of the obvious issue with the letter O and the number 0).

JohnZ

I'd assume it was from a 4-4-2, as that was the overwhelming package that used the Muncie 4-speed; I'm no Olds expert, but I doubt if many ordinary Cutlasses were built with 4-speeds.

DZAUTO

Agreed, no doubt that is very true.
Although, my (76) Cutlass that I special ordered (still have it) in Mar 76 is the base model (Cutlass S) 2dr. It is a factory 5sp car. Out of many, many thousands of TOTAL Cutlass models made in 76, there were just slightly over 900 with the 5sp. In 76 the 5sp was ONLY available with a small V8 (NOT with the 455). In 87, I built a healthy 455 for it and replaced the weak B-W 5sp with a Richmond 5sp. Haven't touched it since.

dannys

my Muncie has some numbers I cannot decode, pass side case is a 3925660, back a little on case is stamped OPO5A
and I think part of a vin 10W1A(or 4) 6178 looks like to me 10W1A6178 tail housing 3846429 drive side cover 3884685 also 2 groves on front shaft 10 spline,, I find some of the numbers , but the stamped number I cannot figure out, ,help if you can

JohnZ

That's a mixture of '68-'69'-'70 parts, but the 10W VIN derivative and other details say essentially it's a 1970 M20 originally installed in a 1970 Nova built at Willow Run.