Component dating in relation to the build date of the car

[Mike S]

What if it was replaced by the dealer under warranty shortly after the car sold? How is a rear repaired under warranty?

[bcmiller]

The axle appears to be a restamp.

It would be very unusual for a housing to fail or if components failed it would be unusual for the housing to be damaged. Normal service work would have been to replace the damaged parts and that’s it.

It would take severe abuse or an accident to damage a housing and that’s not covered under warranty. 

[Flowjoe]

L523425 was final-assembled on or about February 17th, 1969. Not going to have a March 5th axle.

Other Feb Z/28s at Van Nuys had axles built late Jan/early Feb. March axles don't show up in Van Nuys data until mid-March.

Perfect.  This is what I was looking for.  As I said above, I'm not trying to prove something that is not true but rather trying to understand what this car is (in 2018)

 Thanks William!

...I know that defects during production could send a car off to the side For correction but it seems unlikely it would sit for two weeks or so waiting for a rear end.

There was no "...off to the side." If a component had a problem it was replaced immediately.

Understood.  What I was referring to was this passage from John's article on the assembly process:

"Final Process
The car proceeded down the light repair conveyor to have any minor discrepancies taken care of; for major issues, the car was driven off the end of that line into an off-line repair stall, and was re-roll-tested if necessary to verify the correction. If the car was OK at the end of the light repair line, it went directly to the shipping line. If any paint repair was required, the car went on another short flat-top conveyor that took it through low-bake paint repair, and from there the car went to the shipping line. "

Clearly defective internals on a differential (axle bearings, gear howl, bad carrier or pinon bearings, etc) would not be detectable until the drive test on the rollers.  I though it unlikely that it would take weeks to correct such an issue, if found, but thought I'd ask.

[Flowjoe]

What if it was replaced by the dealer under warranty shortly after the car sold? How is a rear repaired under warranty?

I had wondered the same thing above but realized it would take a pretty significant failure to warrant the replacement of the entire housing.  I think Bryon has the right of it which I can support anecdotally. 

Our '69 GTO was bought by my parents and it had a rear end failure while under warranty (left my Dad and the Neighbor kid to walk back to the house from the freeway and call a tow truck). Pontiac simply repaired whatever was bad inside and returned the car.  I was too young (and unwise in the mechanics of cars) to understand the exact nature of the problem then.  Years later (~2013) when we rebuilt the rear end we found severe scarring on the "Saf-T-Trac" carrier and on the inside of the housing.  Clearly something went very wrong but Pontiac (GM) did not replace the entire housing.

I've seen some pretty horrific rear end failures come through our shop (had a Bronco with an 8.8 spit the cross shaft out the cover while turning a corner on a down town street).  Bryon is right again that generally the housing survives (even in the case of the Bronco).  There are always exceptions, like pinion or carrier bearing failures that allow rotating components to eat into a housing, but normally it is an accident or hard usage which damages the housing.

[69Z28-RS]

It matters very much as to the 'attitude' of the owner what is done to *repair* a problem under warranty!   I do think it's possible that if a car *very new* as in a week or two old.. suffers a major problem such as a differential breaking, that at the owner's insistence, the entire differential *may* have been replaced.    Warranty issues that can't be decided at the dealer level can be elevated to the regional service representative and they have a bit of leeway in how they address a problem!

What would YOU do if your 2 week old NEW Z28 broke it's rear end?   Aren't these cars supposed to 'nearly race cars'?  (and No, you don't have to tell them you dropped the clutch at 6G... 

[Mike S]

I thought perhaps replacing a bad rear could have been more cost effective instead of replacing something more labor intensive
like a bad ring & pinion as an example, under warranty.

[KurtS]

The repair bay at the end of the line was simple - fix and move on. There isn't room in an assembly plant to store cars - they get in the way real quick.

It is an atypical stamping. The fonts are correct and the cast date is correct. It could be an anomaly due to a process issue. Don't know, but it's not original.

[jdv69z]

I see no issues with the engine stamping and the date lines up well with the car production (mid to late Feb), but the axle stamp date (early march)  is too late for the car (from the factory).

That’s essentially why I posted.  By everything I’ve learned in the last 34 years of messing with 1st gens that rearend is too late to have been on the car when it left Van Nuys.  But it boggles the mind to think that someone randomly found a 3.73 posi with a date that close to the cars build date to stuff in this car.  No one tried that hard nor got that lucky with the tranny.  Even if restamped, as suggested above, the cast date is amazingly close.  FWIW, The car is well worn and shows no signs of an abandoned restoration. 

I know that defects during production could send a car off to the side For correction but it seems unlikely it would sit for two weeks or so waiting for a rear end.

Which brings me back to my original questions about what could have happened in the factory (John??) or warranty parts. 

As always, not trying to make it something it’s not just trying to understand what it is.

On my 69 Z, I originally thought it had the original 892 water pump. Turned out it had been replaced. (probably around 1978) Replacement pump was same part no. 892, but cast date was I 23 8, and engine assembly was 0912DZ. So totally at random it was only a few weeks late from being perfectly in line with the original engine build.

[Kelley W King]

In 78 I bought a two tone blue Caprice. It came in with a bad scratch on the door. The dealer shop tried to match it a couple times. They finally took a door off another car on the lot. I never saw any docs for it.