Question of build date vs. rear assembly date

[nuch_ss396]

Hi everyone,

I have a fast question about a situation that I ran into recently.  I am helping a friend restore an L/78 and the build date of the car is 02C with the rear assembly
date of mid-october.  This is verified by the POP and window sticker. 

My question is this.  Four months seems an aweful long time for a 12-bolt rear to be sitting around.  This rear was a 3.55 posi.  Can anyone tell me the approximate
procedure for selecting components for assembly "back in the day"?  Perhaps JohnZ is near by.........

Thanks,
Steve

[JohnZ]

Kurt S can probably tell you how that spread compares to other similar cars in the database, but the original 4.10 axle in my 02D '69Z is dated February 19th (the car came off the line on February 27th).

The "selection" process was simple - the operator looked at the Chassis Broadcast, took his hoist to the rack with those axles, grabbed the next axle in the rack, and loaded it on the chassis carrier; nobody paid any attention to dates. The axle racks came out of the rail car, were stacked in off-line storage, and were taken to the line one rack at a time. Axle racks held four axles each.

[KurtS]

Steve,
What year and which plant?

[camaro cat]

JohnZ, I notice your Z/28 was built 02D at Norwood as was my L78. My vin is xx5415. Where is your car from mine. About 15 years ago I came across a Z/28 close to where I live that was built 5 cars away from mine.

Loren

[rich69rs]

Although not a Camaro, my other car, a '66 Chevelle, has always been in the family.  It was my grandparents ride, and they purchased it on 30 March 1966.  The car was assembled at the Flint, MI plant in mid March 1966.  I have all the documentation on this car including POP.  The rear axle in this car was manufactured at the Buffalo Gear and Axle plant on 27 Oct 1965 (see code below).  I have also verified the numbers as stamped on the ring gear.  They are:  GM  3790628   1137  65.  The first series is the part number.  1137 is the number of teeth on the pinion (11) and the number of teeth on the ring gear (37).  This equates to a 3.36 ratio, which agrees with the CB axle code.  65 is year of manufacture.

The engine, transmission, and axle codes (and build dates) are as follows:

Engine Block:  F0318DE
Transmission:  C0322D
Differential:  CB1027B

As we all know, there are exceptions to every rule.  My Chevelle definitely has an October 1965 built rear end in a March 1966 built car.  Why the axle lay around from Oct to March (5 months) much in the same manner as nuch_ss396 axle lay around for 4 months before being used is a mystery.  And it would be very helpful to understand why that occurred.  But it is clearly an exception to the rule.  I would not be surprised to have someone state that the rear end in my Chevelle is not original (forget about the documentation) because it doesn't fit the "norm" with regard to its build vs the car's build.  We don't have all of the answers.

[nuch_ss396]

Kurt S can probably tell you how that spread compares to other similar cars in the database, but the original 4.10 axle in my 02D '69Z is dated February 19th (the car came off the line on February 27th).

The "selection" process was simple - the operator looked at the Chassis Broadcast, took his hoist to the rack with those axles, grabbed the next axle in the rack, and loaded it on the chassis carrier; nobody paid any attention to dates. The axle racks came out of the rail car, were stacked in off-line storage, and were taken to the line one rack at a time. Axle racks held four axles each.

Thanks for chimming-in on this John.  I was hoping you were on-line.

John, that makes perfect sense.  However, how does a rear just "sit around" in a rack
for 4 months before it gets selected.  If a rack only held 4 rears, it would stand to reason
that the racks were turned-over on a daily or regular basis.  This is the cause for my confusion.

Kurt, by the way, I am referring to a 1970 model.

Steve

[JohnZ]

JohnZ, I notice your Z/28 was built 02D at Norwood as was my L78. My vin is xx5415. Where is your car from mine. About 15 years ago I came across a Z/28 close to where I live that was built 5 cars away from mine.

Loren

Mine is 606402, built a little more than two shifts after yours.

[JohnZ]

The "selection" process was simple - the operator looked at the Chassis Broadcast, took his hoist to the rack with those axles, grabbed the next axle in the rack, and loaded it on the chassis carrier; nobody paid any attention to dates. The axle racks came out of the rail car, were stacked in off-line storage, and were taken to the line one rack at a time. Axle racks held four axles each.

Thanks for chimming-in on this John. I was hoping you were on-line.

John, that makes perfect sense. However, how does a rear just "sit around" in a rack
for 4 months before it gets selected. If a rack only held 4 rears, it would stand to reason
that the racks were turned-over on a daily or regular basis. This is the cause for my confusion.

Kurt, by the way, I am referring to a 1970 model.

Steve

Who knows - lots of weird things happened occasionally in the production system in those days; that's why the NCRS allows full credit for dated components up to six months prior to the car's final assembly date in Corvette Flight Judging, although 2-6 weeks is "typical".

[Tinkerr]

A possible explanation is like so many other things that have date codes they are supposed to be rotated old to the front,new in the back.Who's to say that a  individual wasn't unloading the rail car and wasn't rotating the stock.That rack or two sat in the back against the wall for several months.We know GM got more than 2 or 3 the rears at a time.You have 10 racks the forklift driver say's,I'm not moving those, I'll just put these in front,the're all the same. I'll put the rest in that hole over there, I'm off in 20 minute.Something just got buried in the warehouse.The next shipment went right in front. If things are busy,the warehouse is full,you put thing where you can and worry about it later.I worked for Coca-Cola for a # of years and things were alway's buried and didn't turn up until inventory.If you think I'm wrong check the date code on that soda all the way in the back of the shelf, rotation is a necessary evil, but a huge inconvience,not alway performed diligently.Human nature being what it is,these things happen. Just a thought from somebody involved in warehousing and manufacturing.

[Farm Boy]

The argument could be made that a common axle assembly like a 3.08 ten bolt should be dated fairly close to the body date and less common axle combination could sit around for some time before being installed. I doubt very many 70 Camaros were equipped with a 3.55 posi rear end.

[rich69rs]

My '69 RS, 01C build, base coupe, has a non-posi 2.73:1 rear end, code BP, built 10/18/68 at the Detroit Gear and Axle Plant.  My car went through final assembly somewhere around the 19th or 20th of January 1969 at the Norwood assembly plant.

[Mark]

My 69 Pacecar has an 0429 built 3.07 12 bolt non posi rear axle.  The car rolled off the assembly line sometime just before midnight on 4/30/69.