"Peening" on late production 69 axle codes

[cook_dw]

No reason to pull all the verbiage from the other thread.  No comments about respect or opinions.  What I would like to see if there are others out there in the Aug - Oct timeframe that have the "peened" area over the "C".

[cook_dw]

More info.


Info as I have it currently.  Please feel free to add your info.  Thank you.

[69Z28-RS]

Well..  when the other thread was closed/slammed/whatever happened to it, I lost the data I posted relative to the optional Nova rear gear ratios for 1970 (The '70 Nova rear for multiple leafs would have been identical to the *late* '69 Camaro rears where the ratios existed on both cars!  (Looked it up again)...

The 'BS' ratio (3.31:1) WAS available on the '70 Nova, so the rear end noted without the 'C' peened would most likely have come from a Nova.  The 'BU' and 'BE' ratios were not available on the '70 Nova, thus the leading 'C' for the 1970 year would not have been indicated for those ratios, but late '69 Camaros with BU or BE ratios *might* have been stamped with the leading 'C' (for 1970 models) in the axle plant before someone noted they were going into '69 model cars (Camaros)... (and obliterated the C)...

[BULLITT65]

I am hoping Bentley has some contributions. I think he mentioned in the other thread that he had seen a BE with a peened C. I also am going to inquire with a nova site I am on and see if I can possibly get some examples from them.

[69Z28-RS]

Based on our hypothesis (that 'late' Camaros that used rears that other '70 model cars) got the C's peened/obliterated...  Nova rears would NOT have the peened characters (if the rears are original to Novas) since Novas did not have extended production from '69 leading to the '70 model year.   Only Corvettes and Camaros (suffered or benefited?) from the extended production and corvettes used a totally different rear end type (IRS)...

That said... since Novas and Camaros share the same rear end width, there have been a LOT of swapping of rears between the two car models over the last 40+ years!

[cook_dw]

I understand the basis of the scenarios and hypothesis but for me personally do not want to post any of that at this point.  I would rather let the data speak.  I also realize that the spreadsheet above is "down and dirty" and will need to be expanded on in the future but I just wanted to get something down.


1970 Nova differential codes

CBA - 2.56 open 10-bolt
CBB - 2.56 posi 10-bolt
CBC - 3.36 open 10-bolt
CBD - 3.36 posi 10-bolt
CBL - 3.07 open 12-bolt
CBM - 3.31 open 12-bolt
CBN - 3.55 open
CBP - 2.73 open 10-bolt
CBR - 3.07 posi 12-bolt
CBS - 3.31 posi 12-bolt
CBT - 3.55 posi
CBW - 4.10 posi 12-bolt
CPA - 3.08 open 10-bolt
CPE - 3.08 posi 10-bolt
CPI - 2.56 open 10-bolt
CPJ - 2.56 posi 10-bolt
CPO - 3.08 open 10-bolt
CPR - 3.08 posi 10-bolt
CPX - 2.73 posi 10-bolt

[KurtS]

Edited, a lot.
Simple rules to this post - post facts and data. Postulate after data is accumulated.

[KurtS]

Going through my pictures and only listing the axles were the C was visible and clear. If it wasn't a good pic, I didn't make a call.
Interesting that there are dates like CBU0829 that are both peened and not peened. 1 BE was peened, several weren't.
FWIW, late 69 BB engines also had the C added to the application code.

not peened
CBA0804
CBS0805
CBL0806
CBS0820
CBL0812
CBU0819
CBQ0821
CBA0827
CBU0828
CBU0828
CBU0829
CBS0829
CBT0902
CBU0915
CBU0918
CBU0918
CBT0922
CBT0924
CBS0926
CBM0928
CPI1003
CBU1007
CBU1008
CBU1009
CBT1013
CBR1015
CBT1021
CBM1022
CBM1028

peened
CBU0818
CBU0818
CBU0827
CBU0829
CBU0829
CBU0910
CBU0922
CBU0929
CBU1003
CBU1006
CBU1017
CBU1022
CBU1017

[cook_dw]

Peened BE  0922G2

Original diff under a 20K mile original COPO.  Grease was removed for the first time this past July.

[bcmiller]

Note here from the Chevrolet Dealer Service Information Bulletin dated September 29, 1969.

The first C in the code designates it as a Passenger (car) type axle versus Truck. This is for very late 1969 model year axles and continued into 1970.  Things changed again in 1971. Remember that GM "Corporate" 10 bolt axles were gradually implemented in the early 1970s.

[bcmiller]

Thought the information above might be of interest to some.

[69Z28-RS]

Bryon,

Is there some 'new' information on that documentation, that isn't obvious? 

[cook_dw]

Thanks for posting.

[bcmiller]

Bryon,

Is there some 'new' information on that documentation, that isn't obvious? 

GM documentation which shows why the C is supposed to be there.

Production code numbers will contain prefix letters, production date numbers and a suffix letter.

[69Z28-RS]

I didn't know there was any question about that for 1970 model year Chevrolets....

[bcmiller]

Gary, it’s for very late model year 69s as well. Did you read the date of that in my post?

There is no documentation that “peening is required”.  😀

[69Z28-RS]

Bryon,

That directive was for ALL Chevrolets (not only Camaros), and it corresponded to the normal 'date' for coming year changes (ie. For 1970, all Chevrolet model differentials got the C added).   

But what happened in parallel, was that '69 model Camaro production was 'extended' past the normal time, and the 'C' was NOT specified for '69 model differentials, and I believe that's why the C was peened out for late Camaro differentials.   Not surprising to me at all, as things happen in different locations at the same or similar times, and changes/corrections have to be made..   The peening over of the 'C' for '69 model Camaro diffs. was one of those things.

[bcmiller]

Gary. Wrong. They weren’t factory peened.

The axle plant didn’t change their policy or operations just because the model year was extended. Did you read Kurt’s earlier post? I am 99 percent certain there were modifications done after vehicle assembly.

You have your opinions and I have mine. Let’s leave it at that.

[ZLP955]

By 'factory' are you referring to the axle assembly plant, or the 2 Camaro assembly plants?

[69Z28-RS]

Gary. Wrong. They weren’t factory peened.

The axle plant didn’t change their policy or operations just because the model year was extended. Did you read Kurt’s earlier post? I am 99 percent certain there were modifications done after vehicle assembly.
...

Bryon,  I'm curious as to WHEN/WHERE you believe ALL the late '69 Camaro differentials had the inadvertent 'C' removed (or peened over)...  Or are you still contending that thousands of owners individually peened over the 'C'??

[KurtS]

In my mind, there's no question that the assembly plant peened the prefix C on these axles. I'm kind of baffled on why they thought they needed to though. It's also notable that it's not all late axles, just a subset. Wonder if it was just one supervisor....

[ZLP955]

In late '69 MY production (including the timeframe that peening has been observed), did the 'C' appear as a prefix to the axle code on Protect-o-Plates?

[cook_dw]

No Tim.

[bcmiller]

In my mind, there's no question that the assembly plant peened the prefix C on these axles. I'm kind of baffled on why they thought they needed to though. It's also notable that it's not all late axles, just a subset. Wonder if it was just one supervisor....

Why are they not all the same then? Why didn’t they use the same tool to do the task? Why was it ongoing intermittently for 2 months?

[cook_dw]

Why are all engine pad stamps not identical.?.  Why are screws left out of locations?  Why weren’t the same fonts and locations of stampings consistent throughout production.?.  Human error and it was over 50 years ago.  Although most things were pretty standard there are always anomalies..  This is just another one of those things that are not cut and dry.  I would like to see this thread continue with fact based posts but I guess that isn’t gonna happen.

[KurtS]

Why are they not all the same then? Why didn’t they use the same tool to do the task?

No one knows. Since it was not widespread and was not implemented on all axles, I would say it wasn't a high level edict. Therefore a procedure was not defined and documented. Leading to implementation that varied.
A good example of why GM liked and followed their procedures - consistency.

[69Z28-RS]

In my mind, there's no question that the assembly plant peened the prefix C on these axles. I'm kind of baffled on why they thought they needed to though. It's also notable that it's not all late axles, just a subset. Wonder if it was just one supervisor....

You guys have more data points/info that we readers do, but I've seen enough examples of 'consistent' peening to know that it had to be done in 'a' GM plant somewhere; probably NOT the axle plant, so that leave the assembly plant as the only possibility.  And unless I'm mistaken, all of the late '69 Camaros were assembled in the Norwood plant, so that narrows it down to be a 'time frame' inconsistency.  Do we have enough data to make an attempt to narrow in on the time frame when it was done?  Or was it so inconsistent that we have to deduce it was a particular supervisor on a particular shift that did it?   Can we expand the data listing we have by listing the VIN or date of the car the rear end came from?   That might give us some better 'timewise' information since rears were not used sequentially as the VINs themselves.

The ones I've seen here on this thread that appeared to have been 'peened' seemed to have been peened by multiple strikes by a blunt faced' small circular tool.  If there's examples of this peening which seem different than that, I'd love to see an example?

The service bulletin that Bryon posted doesn't really give us the dates for which the Axle plant received the information for changing the stamping of 1970 model year axles, but since they indicated the model year change for 1970 MY  the implication is that the dealers already had the information on 1969 axle stampings.'

I noticed that Corvettes were also on the list of Chevrolets which were to get the 'C' for '70 production.  I have an August built '69 Corvette that I could check on the stamping to see if it's 'AM'  or 'C AM' as the '70's were, but I don't recall ever hearing anything about a discrepancy on "Corvette axle stampings', but of course the assembly plant for Corvettes was St Louis.

[bertfam]

I noticed that Corvettes were also on the list of Chevrolets which were to get the 'C' for '70 production.  I have an August built '69 Corvette that I could check on the stamping to see if it's 'AM'  or 'C AM' as the '70's were, but I don't recall ever hearing anything about a discrepancy on "Corvette axle stampings', but of course the assembly plant for Corvettes was St Louis.

My October 21st, 1969 assembled L36/M20 Corvette has its original axle and it's dated 2 CAT 10 6 69 (October 6th, 1969, Heavy Duty 3.08 Posi assembled on the 2nd shift).

Ed

[69Z28-RS]

Ed,

Did you check the stamping on the differential in your Corvette?   Is it notated with the 'C' in front of the code?

[bertfam]

Did you check the stamping on the differential in your Corvette?   Is it notated with the 'C' in front of the code?

Yes I did and yes it is. And by the way, there's no mention of "peening" in the latest (5th edition) 1968-1969 Corvette Technical Information Manual and Judging Guide (TIM&JG). It only states “Those 1969 cars produced after September 1969 have 1970 differential codes.”

Ed

[69Z28-RS]

Thanks Ed,   that's an interesting piece of information...  I need to check my August build '69 and see what it is...     So the implication from that comment is that ALL of the late '69 Corvettes were shipped with the '70 diff codes...   

That leaves the Norwood Camaro plant as the only other assembly plant  with the quandary, and that plant was apparently inconsistent on how they addressed the discrepancy.. 

I really think we need to add the 'car production date' to the data listing for these late '69 Camaro differentials to narrow in on the dates which distinguishes the dates for how Norwood assembly  handled that discrepancy.

[luv2sixty9]

It should also probably be documented if the housing is an 860 or later 341 housing

[KurtS]

You guys have more data points/info that we readers do,
Can we expand the data listing we have by listing the VIN or date of the car the rear end came from?   

I listed all the info I have. A couple of new cars have shown up since - discussed on the site and added below.
It would be a whole lot of work for me to attach build dates to that data.  And several are not tied to cars.

not peened
CBA0804
CBS0805
CBL0806
CBS0820
CBL0812
CBU0819
CBQ0821
CBA0827
CBU0828
CBU0828
CBU0829  09C
CBT0902
CBU0915
CBU0918
CBU0918
CBT0922
CBT0924
CBS0926
CBM0928
CPI1003
CBU1007
CBU1008
CBU1009
CBT1013
CBR1015
CBT1021
CBM1022
CBM1028

peened
CBU0818
CBU0818
CBU0827
CBU0829  09C
CBU0829  09C
CBS0829  09C
CBU0910
CBU0922
CBE0922  09E
CBU0929
CBU1003
CBU1006
CBU1017
CBU1017
CBU1022
CBU1028  10E

[69Z28-RS]

That's the first time I've seen the data you have in 'that format', and it is surprising that there's not much we can determine from it re 'timeframe'...  some put into cars the same week with and without the peening.  Maybe all we can determine is that 'some were' .. and 'some weren't'..  and we're not going to get any further information unless some old fella who was working in the Norwood plant comes forth and says 'I did it'...

Thanks for collating the information~   

[67CruiseMaster]

Maybe one shift was doing it and one wasn't. my .02cents

[BULLITT65]

Maybe one shift was doing it and one wasn't. my .02cents

That was my thought. I have noticed other rear end stamp discrepancies and those lined up to be from the same shift.

[KurtS]

That's the first time I've seen the data you have in 'that format',

That data has been in this thread since 9/27/2018. http://www.camaros.org/forum/index.php?topic=16781.msg153462#msg153462

[bcmiller]

It is not the same shift. I verified that.

When you get right down to it - it doesn't really matter WHY these have been peened. What matters is that all documentation that has been found so far indicates that the C should be there.

Little sidebar for you.
I am a shift supervisor in my 23rd year.  No not for an axle plant or for a vehicle assembly plant, but for an outfit that produces products every day. These products are to be produced in a specific format. If inconsistencies develop from one shift to the next, those are addressed immediately. That means in a day or two, typically at shift change. If it can't be handled that way, then higher level management is brought in and it is fixed in less than a week. If another shift is making work for me, by producing products out of tolerance or format, that doesn't make me happy.

Let's say though that in this axle case that someone continues to put an extra C stamped on something that I don't think belongs there. If it keeps happening, I am going to develop a tool for a "one and done" fix to get rid of that C. What we have seen in these peened cases are multiple strikes and not using the same tool. For a production line, that doesn't make sense. Consistency is important and time is money. I don't think it happened at the axle plant.

It also does not make sense that it happened with vehicle assembly. Axles were labeled with tags on the end of the brake drums or in other ways. It was not necessary to look at the stamping on components as cars were being put together.

This anomaly went on from about mid August through the end of 69 model year production - about 2 months. In the real world, it does not make sense.

I might ask JohnZ what he thinks about this topic.

[ZLP955]

It also does not make sense that it happened with vehicle assembly. It was not necessary to look at the stamping on components as cars were being put together.

Somebody on the line had to read the stamped axle code to transfer that info onto the Protect-o-plate. I mentioned the PoP earlier and Darrell confirmed late production PoPs don't show the additional 'C' seen after August. The CRG PoP decode article mentions that only a certain number of characters were used for each drivetrain field. 7 for rear axle code, beginning with 2-letter prefix. Maybe this is pertinent?

[bcmiller]

It also does not make sense that it happened with vehicle assembly. It was not necessary to look at the stamping on components as cars were being put together.

Somebody on the line had to read the stamped axle code to transfer that info onto the Protect-o-plate. I mentioned the PoP earlier and Darrell confirmed late production PoPs don't show the additional 'C' seen after August. The CRG PoP decode article mentions that only a certain number of characters were used for each drivetrain field. 7 for rear axle code, beginning with 2-letter prefix. Maybe this is pertinent?

Possibly.

[67CruiseMaster]

I think it had a lot to do with the extra time for the 69 model run since 1970 models came out late.

[bcmiller]

I think it had a lot to do with the extra time for the 69 model run since 1970 models came out late.

Here is the thread with background information on the topic. This thread morphed/split out of that one.
http://www.camaros.org/forum/index.php?topic=10375.0