1965 GTO rearend code
 

I need a rear for my GTO but can not find what the casting code should be. Does anyone have any info or a sight I can go to to find the code ? I know the axle code is YH and the date is J,K or 1st week of L if anyone has a lead on one. Thanks

Casting #9779822 date code is next to it is. letter day year k 12 4 ect.

64 car is different......66 up is wider........65 one year only!

1965 GTO rearend
 

When I google that code it comes up as an Olds rear. The guy who has the rear says it has only 1 rib on each side of the carrier which shows to be a Buick rear.:confused:

1965 GTO rearend
 

Could that attachment showing the 3 style rears be for years other than 1965 ?

What I wrote my be the only thing I know about a GTO. LOL
Not sure if Olds shared it or not. They call them BOP rears?

There were different foundry's casting cases and there were up dates. You may see a larger 1 or 2 or 3 ect. on case. But this is not important. If you are looking for a date code to match your Dec car.

If its wrong some one will chime in

I have an available '65 Pontiac rear, but a May '65 date code. I believe it is stamped for a 2.78 axle ratio IIRC.

Olds for sure and maybe Buick also apparently did share the same center casting.

9779822 is a Pontiac engineering issued part no. It is for the casting only and does not identify the Axle Tubes & Diff Housing assembly.

What I do not know is whether Olds (or Buick) used different axle tubes pressed into the center casting. So I cannot say if a '65 Olds Cutlass rear Housing is completely identical to the Pontiac. Possibly same Housing Assembly but different ring & pinion gears were offered, I just don't know anything about Olds to be sure.

The stamped codes will be different for sure but that is a trifling matter.

If all the dimensions are correct, then I would say it will work for you.

If you need dimensions to compare it to my Pontiac Housing just ask.

1965 GTO rearend
 

Is that a picture of your rear from your 65 or a picture you found online ?

Picture is from file.

I have 64 and 65 housing and a 70. all are different in some way. But all these will bolt in.

64-65 is 54.25" flange to flange.........66 up is wider 3/4"

The gears and case interchange. Case is different for different gear ratio's. Check with people that sell gears and cases for interchange.

More help. Note date. This casting # 54.25" wide and you found the correct housing. Gears and carrier you may have to change.

1965 GTO rearend
 

Is the rear for sale or another one that you have ?

Ask John V first He was first to post one. But the 64 I will sell. Have housing only.

1965 GTO rearend
 

Johns is dated for May, I will need a oct,nov or early dec of 64. What is the date and axle code on your 64 ?

My 64 rear is cast in 63. Yes you need the housing that I posted pic of. Thats for my 12c 65 car. Sorry.

Remember if its about the correct Date the 64 rears won't help you, diff. casting # and they look way different. You need 9779882 casting. The year is cast in the housing remember.

Any chance at all to purchase your 65 housing ? Maybe put an inflated price on it.

What is the gear ratio code ?

No .......can't help With that. Will PM u if find something u can use.

Is the casting code for your 64 housing 9772969? What is the date code, please? Thanks, JBA

65 rearend
 

This rear is for my 65 GTO. The casting code is 9779822 and the date I need is K or early L of 1964 with a gear ratio code of YH.

PICTURES Very few pits in tubes.

dld, that Housing is really throwing me for a loop. Is it for sure an A-Body Housing?

The p/n on the casting really threw me, 9773722 was a Pontiac p/n, but not one I'm familiar with. The p/n "vintage" certainly seems correct for the '64 Model Year and the I33 cast date is a good cast date for an early built '64 (Sept. 3, '63).

The '64 A body Housing that I'm familiar with has p/n 9773369 on it, although they were not raised cast as you see on your 9773722 Housing or the '65 A-Body 9779822 Housing.

I don't think the 9773369 was stamped, I think it was cast that way, but it will appear "debossed" as if it was stamped, rather than raised character. There is what appears to be a cast date code but it is not the same code style as used on this one, rather it may have been a Julian type so that it might read 114 for the 114th day of 1964 (perhaps a day in April?).

The first time I learned that the '64 Housing even had a p/n on the casting was in this thread:

http://forums.maxperformanceinc.com/...hlight=9773369

Chronologically, 9773369 was issued before p/n 9773722. But the early cast date on yours would suggest this is not a superseding p/n.

Possibly, as was done with some other components, it may represent an alternate p/n that was cast using different metallurgy which allowed for different foundries to supply the part.

So now, I'm very curious.

Is the numeric axle ratio code stamped near the vent with a P prefix?

Does this 9773722 Housing have the ears for the small bushings, same as the 9773369 Housing?

Does anybody else have the 9773722 Housing installed in an original '64?

I wonder if the Final Assembly Plant had anything to do with which Housing was used?

gtobreaux, you ask if the p/n was 9772969, where did you come up with that p/n?

65-64 rears
 

John

I got this rear housing at Carlisle flee market. Along with it were a lot of 64 parts. The vendor said he was parting out a 64. Half of it was there.

I measured housing ,it is same as 882 housing 54.25" flange to flange.

No stamp on tube. But I thought 64 and early 65 color coded backing plate and axle center to ID ratio and type?

Yes has small upper bushings

I also heard that there were several foundries and the # 2 3 4 ect. was to ID the series of housing?

If by "series" you mean a revision to that p/n, I suppose that is possible. It might also mean a particular mold, but revision no. also works for me.

Since the same housing was used regardless of internal gear, it should not have anything to do with the "series" of the Differential Carrier which was internal to the Housing (the Diff Carrier "series" depended on the ring gear being used).

I'd sure like to know if anybody else has ever come across this p/n on a '64 Housing.

You say it measures 54.25" flange to flange. Did you measure straight thru the axle tubes and did you include the thickness of the axle flanges on the end of the tubes?

If you read the thread I linked, the '64 9773369 and the '65 9779822 housings that I have all measure 54.50" flange to flange.

1/4" narrower doesn't seem like much, but still would be strange to me and I think an awful lot to be considered a "tolerance" error.

And you say it is same dimension as a 9779822 but that doesn't check against mine which measures 54.50".

Since it is a Pontiac p/n on the casting, it sure seems correct. But the lack of a ratio stamp code makes id'ing it as having originally come from a '64 Pontiac A-Body difficult.

Would sure like to hear if others have this casting under their '64.

According to a Chevelle site, the '64-'67 Chevelle rear Housing (Chevy p/n 3839390 in '64) measured 54.25" flange to flange.

Now perhaps it really was narrower than the Pontiac housing by 1/4" or maybe my measurement is off or the common wisdom is off.

But there is the possibility that your Housing was a Pontiac p/n assigned to a part that Pontiac could produce for Chevy. In '64, Pontiac issued a p/n for a Frame that was specified for the Chevelle. Not trying to throw any doubt on the correctness of your Housing for the '64 Pontiac A-Body application, just grasping for explanations about a part I have never seen or heard of.

My bearing caps aren't accessible but I happened upon a thread about a 9779822 '65 Housing and the Bearing Caps in it show p/n 9773721! No surprise that the matching bearing caps were issued a p/n in consecutive order with the cast Housing section that you have and carried over for use in the '65 rear.

I wonder what cap p/n is in my 9773369 rears?

Another '64 mystery, I love it!

well ???? I did measure from outside backing plate flange to o/s. Straight across backside (no cover) on housing. My 65 822 housing is the same.

When I used the term series I meant the casting design.

I think it is more possible that instead of Chevrolet it would share with Olds and Buick.
There is also the chance you 369 housing was from a 63 f85 or a skylark.

Your idea of plant use could be correct. The Balto. plant build olds half year in 64 and Buick the entire A body run into the early 70's. These were on the very same line. The BOP cars shared the same ratios I think ? This would cut down on inventory and cost.

One other point the vendor I bought housing from only had the parts of the 64 car set out. No sure thing but looked like it was from that car. The bushings also were the 64 small type.

65 Rearend codes
 

I have a question about the 64 and early 65 GTO rearend coding. Did they not come with a stamping on the axle tube. I spoke to a guy today with a L164 date on his rear, but he said there was not a gear ratio stamping on the axle tube.

The 64 and the 65 housing that I have don't have those markings on the tubes. The tubes on both are pretty clean.

The resto book that I read stated that the 64 and the early 65 rears were color coded.I can't confer more than this.

Could you please tell me the name and author of the book so I can properly mark my rear? Thank you

Found one source. Some conflict to what I posted on stamping.Look in The GTO Association of America ID Guide buy Eric White.

Eric White is what I would use. I wouldn't trust the internet "go to" sites.

[QUOTE=John V.;4060351]dld, that Housing is really throwing me for a loop. Is it for sure an A-Body Housing?

The p/n on the casting really threw me, 9773722 was a Pontiac p/n, but not one I'm familiar with. The p/n "vintage" certainly seems correct for the '64 Model Year and the I33 cast date is a good cast date for an early built '64 (Sept. 3, '63).

The '64 A body Housing that I'm familiar with has p/n 9773369 on it, although they were not raised cast as you see on your 9773722 Housing or the '65 A-Body 9779822 Housing.

I don't think the 9773369 was stamped, I think it was cast that way, but it will appear "debossed" as if it was stamped, rather than raised character. There is what appears to be a cast date code but it is not the same code style as used on this one, rather it may have been a Julian type so that it might read 114 for the 114th day of 1964 (perhaps a day in April?).

The first time I learned that the '64 Housing even had a p/n on the casting was in this thread:

http://forums.maxperformanceinc.com/...hlight=9773369

Chronologically, 9773369 was issued before p/n 9773722. But the early cast date on yours would suggest this is not a superseding p/n.

Possibly, as was done with some other components, it may represent an alternate p/n that was cast using different metallurgy which allowed for different foundries to supply the part.

So now, I'm very curious.

Is the numeric axle ratio code stamped near the vent with a P prefix?

Does this 9773722 Housing have the ears for the small bushings, same as the 9773369 Housing?

Does anybody else have the 9773722 Housing installed in an original '64?

I wonder if the Final Assembly Plant had anything to do with which Housing was used?

gtobreaux, you ask if the p/n was 9772969, where did you come up with that p/n?

After rechecking the unit in storage, the number is actually 9773369, with Julian date 323 (October 19, 1963) - the vehicle build date is 10B - which doesn't seem to fit

[QUOTE=dld;4043840]Ask John V first He was first to post one. But the 64 I will sell. Have housing only.
What is casting number on 64 housing you would sell, please? What is date code, please?

gtobreaux

If that question is to me .It is the one I posted pics of

That Julian date deal sounds like a vendor.
maybe McKinnon or Detrot Gear and Axle........ Ect.

I'm not sure if this has anything to do with the existence of the 9773722 Axle Housing, but here is what I believe to be true about the Axle Tube markings.

For '65, the Housing "should" be cast p/n 9779822, has the new for '65 ears for the larger on housing bushings. Some late built '64s might have gotten Rear Axle Assemblies with this casting but the stamped codes should be '64 style.

For '65, Pontiac went to a new Manifest Code system using 2 characters to identify components of the Final Assembly build.

This was true for Engine Assembly identification (WS, YT, etc.) and for Rear Axle Assembly identification. In the case, of the Rear Axle Assembly, the 2 character stamped code identified the axle ratio, the differential type (open or locking), and also the brake type (standard or metallic) since the Rear Axle Assembly was installed at Final Assembly with the brakes already in place.

So for example, it was possible to equip a '65 GTO with the 3.23 axle ratio with or without optional Saf-T-Track locking differential and with or without the Metallic Brake option.

The (4) Manifest Codes used were WF (std brakes, open diff), YF (std brakes, locking diff), XF (metallic brakes, open diff) and ZF (metallic brakes, locking diff). Note, the 2nd character F in the Manifest Code related to the 3.23 axle ratio.

'64 identification was done differently.

The '64 Tempest Shop Manual explains how the Rear Axle Assemblies were supposed to be marked. This consisted of a color code system on the end of the axle shaft plus a numeric ratio stamped on the axle tube.

At mid year, Pontiac issued the attached Service Craftsman News (not dated, but it was the 1st SCN issued in Calendar Year 1964, so perhaps distributed in Jan. or Feb. '64 (the last issue distributed for Calendar Year 1963 was No. 7 and dated "Nov.-Dec., 1963" and typically the SCN's were issued about every other month. FWIW, the last one issued during Calendar Year 1964 was No. 6 dated "Dec., 1964").

SCN No.1 1964 included information about a change in the way the 1964 Tempest Rear Axle Assembly was identified "Due to changes in manufacturing procedure".

These changes eliminated the use of the color code on the end of the axle shaft to ID the ratio. There would still be a color code on the end of the shaft but it was not to be used to identify the axle ratio. That could only be done by reading the stamped code on axle tube.

Now, if you read the '64 Shop Manual, it describes the stamping on Page 4-5 and on Page 4-24, there is an illustration of it for a locking differential code.

For the Open Diff, the numeric ratio only would be stamped. For the Locking Diff, the numeric ratio would be followed by an L.

A 3.23 Saf-T-Track Axle Assembly would be stamped "3.23 L" according to the Shop Manual.

In actual practice, the stamped codes that I have seen are always preceded by the letter "P".

So you would find "P 323 L" stamped on a 3.23 Saf-T-Track Axle Assembly. I omitted the decimal. If that was actually stamped, I'm not sure you would ever be able to see it clearly.

The SCN might be somewhat misleading in that the color coding id was replaced with the stamped number on the axle tube, as if the stamped number was not being applied early year.

I do not believe that is true. The Shop Manual says otherwise so I believe the correct interpretation is that the SCN is simply informing the Dealer Service people that the color coding can no longer be used to ID the axle ratio, only the numeric code that was stamped on all '64 Tempest Rear Axle Assemblies should be used.

It is not clear what the purpose for the "P" might have been in this identification. From what I have found, the '64 Olds F-85 (the Olds A-Body) also had the same stamped codes and an Olds site suggests "P" indicates the vendor. This reference did not make it clear if "P" meant Pontiac was the vendor or if any other vendor supplied Rear Axle Assemblies.

Buick Specials may have used the same rear but decode info on '64 Buicks is impossible to find.

I haven't seen a great many, but I have always seen the "P" prefix on the '64 axle tubes along with the numeric ratio.

dld, p/n 9773369 was issued way too late to have been used as an O.E. p/n for any '63 application. Also, the O.E. '64 Tempest Differential Case p/n's were typically 977338*, so issued around the same time as the 9773369 cast housing p/n.

The p/n 9773722 was issued just a short time later and long before any part nos. were being released for the '65 Model Year.

If p/n 9773722 was a superseding p/n, it would have superseded 9773369 before '64 production began.

Since there are a lot of 9773369 housings in existence under '64 Pontiac A-Bodies, I think the best explanation is that these were alternate p/ns. As I suggested before, perhaps from 2 different foundries.

dld, the dimension difference was bugging me so I just went out to doublecheck my measurements for one of my 9773369 rears and also the 9779822 rear.

Looks like I screwed up when I posted in that earlier thread. Mine both measure 54.25", same as you have measured. Hope I didn't foul anybody else up.

gtobreaux, I wouldn't be so quick to think the julian date doesn't fit a 10B Time Built Data Plate code.

The Data Plate code does not tell you the date when the car was final assembled.

We have no idea where the housing was cast even if you can be positive that the 323 means it was cast on Oct. 19, 1963. We have no idea how fast the casting moved from the foundry to Rear Axle Assembly and we don't know where the rear was assembled.

All of that may have happened at the Pontiac Complex. I know for certain that blocks were cast and wound up in Engine Assemblies that were original to all sorts of '64 Pontiacs final assembled at the Pontiac Complex that seem to have "impossible" block cast dates for the Time Built codes on the Data Plate (when I recorded them, these were often in run of the mill Pontiacs, not highly restored and therefore "suspect" examples).

Understand that whatever the meaning of the Time Built code, it was coded by Fisher Body before the Body Assembly reached the Body Bank and the final assembly sequencing of the Body Assembly was not established until the Body Assembly got to the Body Bank.

Your rear might not be original to the 10B car but I'm not sure how you would prove that.

John, it appears that your 64 method of decoding rear diff assembles carryover to 65. At least to Nov.

After posting that one of my rear housings had no markings I looked a little more and found some. (imagine that)

I suspect that the P is assemble plant code . It appears that gm had many. Just as a example the guide Corvette buy the numbers list one for 65 and up to 8 for 72. These are all one letter codes

As to the Olds diff. I made a call to my old Balto plant super. He informed me that the olds and Buick used the same rears as Pont. He said it was a BOP division of sort That grouped parts to share in mfg. to save time and money.

Where is Alan Clovin when you need him.

65 rear
 

Is that 3rd picture on the 9779822 rear?

Yes

I know this is an older thread, but since I just went thru my reared I thought I would add this. Attached is my (I believe original) casting number from my axle housing. It is a Fremont car built on the 19th of November 1963. The casting number on my housing is 9773722, cast on October 14th 1963. If I’m reading it correctly.

Yes that’s correct.
Oct. 14, 1963

Looks correct, Mine was built Feb 1st and also from Fremont, mine had the older PN rear end and had a julian date. Interesting to see, this must have been when these rears started to change. I also have a 64 Lemans that would have buit the same week of yours at Fremont and it still had a 9773369 rear as well, what was the ratio your car had? My 64 GTO has a 3.55 posi, and the Lemans has a 2.73 open

My car had the 2.56 peg leg differential with the 215 6 banger. I swapped in a 421 and switched to a 3.23 with a new Auburn posi.