Help with tranny ID
Thread Starter
Drifting
Joined: Jul 2020
Posts: 1,500
Likes: 323
From: San Diego
Help with tranny ID
Im trying to identify the transmission in my ‘68 4 speed and I climbed under the car and found these numbers. Can someone help?
Hortizontally on the side 3857574GM
on the rear near the shifter 3 25660
Hortizontally on the side 3857574GM
on the rear near the shifter 3 25660
Thread Starter
Drifting
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From: San Diego
Melting Slicks
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From: Northeast
Le Mans Master
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From: North tonawanda NY
Drifting
Joined: Aug 2008
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From: Calgary Alberta
More times than not there is a flat flange in the area of the "ears" that bolt up to the bellhousing. There should be a set of numbers which start with the letter 'P". Digits will be a date code- 'P8A01 which denotes to Muncie(P) 1968 Jan 01. The 660 casting number was used in all Muncie designations. The really only way to tell is the M20 will have 2 rings on the input shaft.
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Jd,
I agree with BKarol that looks like 3925660 which makes more sense. That case was used from 1968-'70 but that's just about all the info that number will give. The extension housing 3857584 was used from 1966-'70, with passenger side speedo and 27 spline output shaft. So from this limited info this could be the orig. trans from your car. But you'll have to check those flange numbers like BK posted. As far as M-20 or M-21, can't tell without removing the transmission.
Greg
I agree with BKarol that looks like 3925660 which makes more sense. That case was used from 1968-'70 but that's just about all the info that number will give. The extension housing 3857584 was used from 1966-'70, with passenger side speedo and 27 spline output shaft. So from this limited info this could be the orig. trans from your car. But you'll have to check those flange numbers like BK posted. As far as M-20 or M-21, can't tell without removing the transmission.
Greg
Safety Car
Joined: May 2008
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From: Lafayette Louisiana
Agree
Agree no suffix on every 68 Muncie I have owned. There is maybe a mark like a small "c" where the suffix letter would be but that is likely a casting mark and no indication of M20, M21 or M22.
Last edited by 20mercury; Dec 31, 2020 at 09:23 PM.