69 Muncie Transmission tag (pn?)

[z28z11]

Based on bcmiller's post below, were different PN's used on Muncies based on the *rear end ratio*??  Why would they do that??
(I'm trying to learn my 'Camaro new information for the day'...  

Because each different rear end ratio required a different plastic (I think) gear to make the speedometer read correctly.

Actually, the plastic DRIVEN gear was installed at the car assembly plant. What changed was the internal steel DRIVE gear that was pressed on the output shaft at Muncie;

Actually not pressed on, the gear slips over the tail end of the mainshaft and is secured by a spring steel clip. How do I know ? My '69 Z M20 clip broke, lodged in the reverse gear, and jammed the transmission. I made it to the station I worked at, pulled the trans and found the problem. New clip and back in business. Earlier Muncies pressed on -  

[JohnZ]

Based on bcmiller's post below, were different PN's used on Muncies based on the *rear end ratio*??  Why would they do that??
(I'm trying to learn my 'Camaro new information for the day'... 

Because each different rear end ratio required a different plastic (I think) gear to make the speedometer read correctly.

Actually, the plastic DRIVEN gear was installed at the car assembly plant. What changed was the internal steel DRIVE gear that was pressed on the output shaft at Muncie;

Actually not pressed on, the gear slips over the tail end of the mainshaft and is secured by a spring steel clip. How do I know ? My '69 Z M20 clip broke, lodged in the reverse gear, and jammed the transmission. I made it to the station I worked at, pulled the trans and found the problem. New clip and back in business. Earlier Muncies pressed on - 

Yup - the nylon DRIVE gear and spring steel retainer started in '68.

[Bryan302]

I'm in the process of rebuilding / restoring my M21.  I'm to the point of refinishing the bolts and the 3946798 part number tag and wanted to find out what finish the part number tag was originally?  Was it natural bare steel and painted or zinc plated?

Thanks,
Bryan

[ko-lek-tor]

I'm in the process of rebuilding / restoring my M21.  I'm to the point of refinishing the bolts and the 3946798 part number tag and wanted to find out what finish the part number tag was originally?  Was it natural bare steel and painted or zinc plated?

Thanks,
Bryan

Bryon, I am going to stick my neck out, based on my observations over the years and, think about it, these tags were for the line workers to ID a trans, why would they (Muncie Div., GM) require paint or plating (adding uneccessary costs)? So, I have only observed plain unpainted/ unplated steel stamped tags and I am sure that is how they came. B.

[69Z28-RS]

I'm in the process of rebuilding / restoring my M21.  I'm to the point of refinishing the bolts and the 3946798 part number tag and wanted to find out what finish the part number tag was originally?  Was it natural bare steel and painted or zinc plated?

Thanks,
Bryan

Bryon, I am going to stick my neck out, based on my observations over the years and, think about it, these tags were for the line workers to ID a trans, why would they (Muncie Div., GM) require paint or plating (adding uneccessary costs)? So, I have only observed plain unpainted/ unplated steel stamped tags and I am sure that is how they came. B.

I'm usually with Bentley, and I am here as well... I've never observed any traces of paint or plating on those tags; most are covered in light rust when going untouched.  Suggestion:  evaporust and then a light coast of satin clear should preserve it looking 'new' for a long while..

[bcmiller]

We have agreement.  Those metal tags were natural metal, not painted or plated.   

[Bryan302]

Thanks for the input.  I just had to ask.  If they had been plated, one would have never known, mostly because of where they were located, and the exposure to the elements.  Bentley had a very good point.... Why would they have plated them?  That made very good sense.  So, bare metal with a light clear it will be.

Thanks,
Bryan

[lynnbilodeau]

According to the AIM

3950356  N29 for L48, L34, L35 & LM1
3946797 M20 for Z/28 or L78 (and also COPO although not listed in the AIM)
3950316  M21 for L34
3946798  M21 for Z/28 or L/78 (and also COPO although not listed in the AIM)
3950318  M22 for Z/28 or L/78 (and also COPO although not listed in the AIM)

And I agree, tags were not painted.   But I painted mine just because I didn't want it to rust.