[ITSBACK]

Anyone have any info on this type of sitution? This 65 GTO has a 64 Buick rear with a 355 posi rear. Ive been told that some of the early models had 64 rears and even at times 64 non Pontiac rears and other parts. Only problem is this car has 12C on the data tag. Would this be December 65 or 64. Did they build 65 model year cars at the end of 64? How do you know if its early or late?
Thank you.

[Kenth]

The production for 1965 Pontiac´s started 8-24-64 and finished 8-19-65.

I´d say you´ve got a mid-year, dec third week, produced 1965 car.

I´m having a hard time to believe it came from factory with a 1964 rear-end and certainly not a Buick rear-end.

[Zimtok]

My understanding is that Pontiac didn't have a "Pontiac" Posi unit until mid/late in the 1965 year run.
My 65 GTO with "time built code" of 02C 1 has the original 10 bolt posi unit that is an Oldsmobile rear end.


.

[Kenth]

Oldsmobile did NOT make an 8.2" 10-bolt ever.

Olds first A-body rear-end, the 12-bolt cover with 10-bolt internals "O"-axle, came for 1968 A-body´s.
1964-67 Olds A-body uses a "B" or "P" rear-end.

[ITSBACK]

What did Olds put in their A body cars prior to that then?

[geeteeohguy]

You guys need to talk to Ol' Pinionhead. He knows this stuff in and out. I had a '65 GTO once that was built in Sept'64 and had a '64 dated ring and pinion, etc. I'm sure every other '65 model year built in calendar year '64 did, too.

[Scarebird]

Originally Posted by ITSBACK

What did Olds put in their A body cars prior to that then?

My 66 442 had a 8.2" 3.90 posi from the factory.

[John V.]

We just had a long thread discussing the '64 & '65 10 bolt rears.

I agree, Olds did not produce their own 10 bolt center section in '64 or '65, however they DID have their own p/ns for the complete rear axle assemblies that were installed in their Cutlass and F-85. The Olds rears can be identified by their unique Manifest Codes as stamped on the axle tubes, they were different from the Pontiac Manifest Codes for the Tempest rears even for the same axle ratios.

According to the '65 Olds A Body Assembly Guide, Olds purchased the complete rear axle assemblies from Pontiac OR Buick for installation at any satellite Plant (such as Fremont). At the Lansing Plant, Olds, purchased the Rear Axle Subassemblies from Pontiac OR Buick and added the axles, brakes, and other miscellaneous parts to complete the axle assembly ready for installation on the final line at Lansing.

My own opinion is that the so-called '64 Buick rear end is identified by the cast center housing.

Whether this was truly a Buick designed center casting has not been established.

When assembled by Pontiac, the housing will have a Pontiac p/n on it and the casting was presumably cast at the foundry at the Pontiac complex.

When assembled by Buick, the housing will have a Buick p/n on it and the casting was presumably cast at the foundry at Buick Flint complex.

According to what I was told in the previous thread, both the Pontiac p/n and the Buick p/n housings will LOOK identical. I assume there was collaboration between Pontiac and Buick to develop the design.

Evidence of a cast Housing from a '64 Tempest has turned up which is decidedly different and carried a different Pontiac p/n. This Housing looks like the '65 Tempest cast Housing but has the smaller on housing bushings that were used in '64. Only known of a single example but others may exist.

In '65, Pontiac ONLY used their own Housings, but from what I have been able to tell, two different p/ns also were used in '65. The on housing bushings are the larger ones used on all '65 A body rear axle assemblies.

The commonly seen '65 Pontiac Housing is p/n 9779822.

Reportedly, Buick continued with the same Housing style as in '64 except for the larger bushing ears.

If true, then the '65 Tempest rear would look nothing like a '65 Buick rear and definitely not like the '64 rear.

It is VERY unlikely that a '64 Buick rear would be original to any '65 Tempest since the bushing design change.

GM endured a strike from 9/25/64 thru 10/26/64 and for some of the Assembly Plants (Fremont for certain) the strike continued into Nov. over local grievances (just discussed this on another thread last week here).

Anything is possible given the strike, the grievances of the line workers, etc.

I would want to know how you have established that you have a '64 Buick rear? What p/n is on the casting?

What dia. are the on housing bushings?

I would check for the '65 Tempest Manifest Code stamped on the axle tube. Cars were built by Manifests, it would be nearly impossible for a rear stamped with a Buick Manifest Code to have been installed in a '65 Tempest that called for an entirely different Manifest Code.

Where was the car built?

If the assembly plant where it was built was NOT building the Buick A body, the Buick rear should not have been in the building. Unless it was built by Buick and intended for an Olds A body being built at that plant. But if it was, it would have an Olds Manifest Code stamped on it and still not likely have been installed in a Tempest.

Given the strike, 12C is fairly early but I doubt the timing of the build had much impact on parts selection. I don't think the parts usage was quite so haphazard as you may have been led to believe.

Check out the rear more thoroughly. It may not be exactly what you think it is.

[ITSBACK]

I appreciate all the info here. My source of this info is very knowledgable in this area and when I sent him my first pictures he thought it was a Buick rear which was confirmed by him and yourself when he saw the 1-3/8" bushings on the housing. The car was built in Kansas with a date code of 12C. Tonight when I get home I will post pictures of all the numbers I have found as well and the full housing itself.

[John V.]

The Kansas City, MISSOURI plant was a Chevy operated Plant (the Kansas City, KANSAS Plant did NOT build the A body in '64/'65).

From what I can tell, KC did build the Skylark along with Tempests and Chevelles there in '65 so presumably would have had Buick produced rear axle assemblies in the building since KC should have been installing them in the Skylarks (Buick produced complete rear axle assemblies had their own Buick p/ns and Manifest Codes as shipped to KC just as Pontiac rears had Pontiac p/ns and Manifest Codes issued to identify their complete rear axle assemblies shipped to KC.

My understanding is that the Chevelle 10 bolt was a different design so could not have been used interchangeably in the Buick or Pontiac, just Chevelles (unless they had already switched to the 12 bolt).

The Buick produced 10 bolt might have been substituted in the Tempest since they were in the building but would have had the large bushings in '65. I have just never heard of any evidence of that having occurred. Original owner Tempests consistently report original rears with a Pontiac p/n on the housing ('64 & '65). So I question the knowledge of your source. As I tried to convey and may not have made it clear, I do NOT believe any '64 or '65 Tempest was built with a Buick produced rear axle assembly. All of them should have gotten rear axle assemblies produced at the Pontiac, Mich complex axle plant by PMD, this is evidenced by the Pontiac p/n on the center Housing. The similarity with the Buick produced rear axle assemblies is the visual appearance of the '64 Tempest cast center Housing to the '64 and possibly '65 Buick cast center Housing. I do not know why people have concluded this is a Buick design. I don't know of any evidence that establishes that. From what I gather, the main reason for making the distinction is to convey the idea that the '64 design Housing (both the one cast by Buick and the one cast by Pontiac) is not as stout as the designs that PMD produced from '65 up (with variations year to year). In fact, PMD produced a stouter appearing cast Housing even as early as late '63 for '64 usage but it is not commonly found, so it isn't even clear what the purpose was. Buick may have indeed designed the weaker appearing Housing and shared it with Pontiac. I just have a hard time considering a rear that was entirely produced by PMD, including casting their own Housings and assembling them at their own Axle Plant and calling it a Buick rear, no matter who had design responsibility. In '64, I haven't researched this yet, but PMD always stamped the axle tube with a "P" followed by the numeric ratio. I believe the "P" might have been used to identify that PMD produced the assembly. If true, Buick produced assemblies, in addition to having a Buick p/n on the cast Housing, might be stamped with a "B" rather than a "P", followed by the numeric ratio to indicate the axle assembly was produced in Flint by BMD.

Will be interesting to learn the p/ns and the axle code stamping on yours.

Once we know more about the nos., its origins might be more clear.

[ITSBACK]

Where would I find a stamping on the axle tube?
It was Kansas City, Missouri, sorry about that.

[ITSBACK]

Couple more

[John V.]

Bill, in the pic of the cast center housing, I see 77. I can't speak to Buick cast Housings, never had one. On the '64 Tempest Pontiac cast Housings, this would be the date code. Unfortunately, it is a Julian style date code. Best understanding is that the calendar started counting on the first day of the Model Year so this would mean this casting was cast on the 77th day of whatever Model Year it belongs to. But no way to prove it was '64 or '65 based on the date code alone.

The more interesting no. is one you didn't provide.

On the pic where I see the CFD1 and the large 2, there looks to be the casting p/n off to the left in the pic (opposite of the CFD1).

That should tell us if this was cast by Pontiac or Buick as Pontiac and Buick p/ns have distinctly different p/n formats.

The CFD means Central Foundry Div. This was an GM Div. separate from either the Pontiac foundry or the Buick foundry. I was surprised to see this.

Neither of my '64 Tempests Housings show CFD and neither show any cast identifier where yours shows the "2".

Also, viewing your pic and my assemblies, there appears to be an ever so slight difference in what I call the bushing towers. I was led to believe in the earlier thread that they would appear identical. Not so sure looking at your photo.

Because of these differences, I suspect yours will have a Buick p/n on I, but we shall see.

One of the things that I am taking the word of others is that the '65 Skylark rear axle went to the larger dia. on housing bushings same as Pontiac did.

That is the basis for believing yours must have been originally cast for a '64 application.

Somebody with expertise with the Skylark rear axles would need to answer that question.

[ITSBACK]

I will go look at the housing for that cast number. This is supposed to be a one year only rear for Buick.

[ITSBACK]

OK, its very hard to see but it looks like either 1318 or 1818 is all I can see.

[John V.]

Well that's a bummer.

The '64 Pontiac casting will have p/n 9773369. This p/n was issued by Pontiac Engineering for '64 Model Year use (did not exist for prior MY use) and was not produced after the '64 MY as Pontiac had no continuing use for it. Sometime after the end of the '64 MY, for Service Replacement, PMD specified the '65 Differential Housing & Axle Tubes Assembly for the '64 application (and required you to use the larger on housing bushings), the '65 SR Assembly was put together with the '65 cast center section, which most likely would have been p/n 9779822 although there may have been an alternate '65 Housing cast by Pontiac with a different Pontiac p/n (I haven't collected enough info about that yet). So once Pontiac quit producing the 9773369 for the '64 MY Differential Housing & Axle Tubes Assembly, the cast center section with p/n 9773369 had no reason to be produced by Pontiac.

Buick p/ns were also 7 digit during that era, always beginning with a "1".

The only Buick cast center section p/n that I have been able to discover is p/n 1375689. But it is the '65 up casting with ears for the larger dia. on housing bushings. It appears that it may have been used in multiple Buick applications with differing axle tubes. There appears to have been at least 2 '65 Skylark applications each with specific axle tubes and perhaps even big Buick applications with the same cast center Housing. If so, it is not as easy to identify the Buick application by the cast center Housing as it is with the Pontiac rear axles, since the Pontiac cast center Housing did not have multiple applications until the Firebird came along, but it is easy to distinguish between the A body and F body rears because of the spring style.

The Buick p/n 1375689 also may have been used beyond '65, further complicating identification of rears using this cast Housing.

Both Pontiac and Buick produced rear axle assemblies for the Olds A body, Olds did not have a cast center Housing of their own in '64 or '65. When the Olds rear axle was produced by Pontiac, it incorporated the Pontiac cast center Housing (presumed to be 9773369 in '64, 9779822 in '65).

When Buick produced the Olds rear axle, it incorporated the Buick cast center Housing (unknown p/n in '64, presumed to be 1375689 in '65).

Either way, the Olds applications at least in '65 can be distinguished from the respective Pontiac or Buick applications by specific Olds assigned Manifest Codes stamped on the RH axle tube which differed from the Manifest Codes used for the respective Pontiac or Buick applications.

In the thread recently about '64 rears, Simpson reported a '64 small bushing Buick casting with a p/n he read as 1561912. The last digit was unclear to him.

Since Buick p/ns from that time frame generally started as "13" not "15", I believe the p/n more correctly should have been interpreted to read 1361912.

I have NOT been able to confirm that by any other reports from Buick hobbyists.

I had hoped yours would match to his but the 4 digit p/n you found provides no real help. It could be shorthand for the full p/n or it could represent something unrelated to the p/n.

You might try taking a pic of it with and without flash and posting that. Sometimes the camera will catch details better than you can see with the human eye.

But if it is only 4 digits, I doubt it will help any.

Attached is the pic Simpson posted so you can compare to what you are seeing on yours.

[MarkS57]

Hi,

This is an old thread of course but my question is the ring and pinion gears used in the early Buick & Pontiac 8.2's. Are they the same or specific to the rear? My guess would be they are the same as the aftermarket does not seem to differentiate between the two other than rears "bolt in rear axels".

['ol Pinion head]

The ring & pinions sets used in both the early Buick 8.2 ('64-67) & early Pontiac 8.2's are the same.
Housings were cast differently & original axles were slightly different, though early "short" axles will interchange between the two rears.

[MarkS57]

Originally Posted by 'ol Pinion head

The ring & pinions sets used in both the early Buick 8.2 ('64-67) & early Pontiac 8.2's are the same.
Housings were cast differently & original axles were slightly different, though early "short" axles will interchange between the two rears.

Thanks, much appreciated!

Mark