Eaton Posi assembly date
 

All Eaton 12 bolt posi carriers received a stamped assembly date code. The code was in the format of letter / number / letter. It seems be be fairly well known that J was used for 1969. Do we know the letters used for 1965, 1966, 1967 and 1968?

Thanks in advance.

https://i.postimg.cc/Kjk7yrnH/screenshot-7623.png

https://www.onedirt.com/tech/drivetr...rearend-guide/

This help?

He is asking about the letters stamped on the outer edge of the ring gear flange on the Eaton Posi case. I've got cases that are stamped F, G, H and J. I think everyone knows that J is '69, but what are the others? The 12 bolt was produced from '65 to '72. Did these codes continue the same on the Eaton Posi case to '72?

I think they used letter A to k. For the year (did not use I ) J being 1969 you should be able to count back from there.

So you could have a JJ (October 1969)? By the chart letters are for months up to 1971

It would make sense that they didn’t use the letter I for year - but I swear I had one a few years ago with the year letter stamp being I. I could be wrong or suppose it could be later. Although they stopped being used in production in 1972, they were made much later.

Here is a later one. Year code JC - maybe 1993?

The format is letter number letter. Here is one stamped C 22 H from a 10 bolt 3 series posi.

So assuming that the E would be for the first year of production in '65, then F would be '66, G would be '67, H would be '68, J would be '69, K would be '70, L would be '71 and M would be '72? Can anyone verify this with something from '70 to '72?

70 date
 

Here is jan. 22 assembled rear gear.

Thanks for posting that. The posi assembly date stamp is late 69, fits fine for a Jan 1970 axle assembly.

Would anyone have data from other years they would want to post from original axles?

Nobody?

This unit is from Nov. 11 1968 assembled rear .

Thanks! That confirms I was used for the year.

I bought a May of 67 complete original rear end yesterday and it had H for the year.

So it looks like H for 67, I for 68, J for 69. Thanks everybody!

There is the I. So I was used. So F wold be '65, G '66, H '67, I '68 and J '69. I wonder if K, L and M were '70, '71 and '72?

I wonder too. Hopefully we can get more data points.

So what is D 3 A?.....April 3, 1973
I have one with this stamp.

However, it has a casted date on the side of "40" (February 9) and I thought that was the only date.

I have another one with this stamp. B 1 G " Feb 1, 1966?

It has a casted date on the side of "24" (January 24)

Thanks for posting. Is it in an original rear end?

The only way to really verify dates is if it would be a complete original assembly.

If it's a 12 bolt Eaton with a '73 date then it would not be an assembly line unit because the 12 bolt was not used after '72.

The two that I have listed are loose units that I have lying around, so I don't know what they are out of or the actual date.

I was requesting assistance with the stamped date for the cast dates I know how to read.

IDK, it's an original #140 Easton Posi

Ok - I think you decoded the B 1 G correctly. Not sure on the other.

Verified G is for 1966 from an original 67 Z28.

Do we know wether “H” or “I” was used for 1968? Mike mentioned that he was not sure if “I” was skipped it the alphabet. Thank you in advance for any clarification!

Based on post #12 and the photo there of a 1968 unit it looks like ... I....was used. Often times with dates and castings it is not, that is why I said I was not sure.

Mike

I'm going to bring this up again. I've got a 12 bolt 2 series Eaton Posi with a code that looks like A 6 70, but could be A 6 7C. Did they change from a letter code to a number code for the year in '70?

I have a 11D of 68 car this is the original posi unit

rear end date

Thank you SSL78.

That shows I was used for both the month and year.

I’m bringing this thread back to the top because I need help with a date stamp. It looks to be D 3 D, which would be April 3, but I’m not able to figure out the year.

What is stamped on the edge of the ring gear flange?

There’s nothing stamped there. From what I understand, they were either stamped where mine is or down by the ring gear flange, but not both.