Technical Pontiac/Olds Rearend TECH...post it here...

Can we update this or include a full list of 57-64 rears in total wheel to wheel width not housing width. Actually we need 2 lists , 1 Pontiac and 1 for Olds for the differance of width between the Pontiac and Olds ....

 

I know is is a old post for a reply. I don't think these were available at the time, but since this post Fabcraft is selling 31 spline spools

 

I have no idea what rearend I've got. I think it's a '59 to '64 GM. It has had upper and lower trailing arms that have been removed, a front loading center section, and a 4 and three-quarter inch bolt pattern. The only numbers I can find on it are 543317 and J303. There's also a large number 7 cast on one side all by itself. Any help would be appreciated.

 

Can anybody run the codes on this rear end?

Casting # 522496. Casting date C 11 7

 

I'm getting ready to read this whole thread but before I do. Am I going to be able to find spider gears for a 57 Olds, 29 spline power loc. I just blew mine up. What are my options?

 

Wow, you actually broke the spiders with out destroying the Dana posi. Every Dana I ever broke destroyed the posi carrier and cracked the third member housing by snapping the bolts holding the posi together. In the old days it was not that serious, because they were easy to get. Today the they are hard to find.

Fabcraft should have what you need, if anyone has them. If you hammer you car, dump the Dana rear and get a n Eaton posi. the Danas are super weak and take the housing with them.

 

That translates to March 11, 1957. Should have the 29 spline axles.

 

Everything I've ever read about these rears says there was no posi unit available in 1957. (But I learned long ago never to say never) Supposedly the first ones came out in 1958 and that would make them a 1 year only unit due to the 29 spline axles. Fabcraft will definately be your best bet but the 29 spline posi units are pretty rare.

 

Guys, you keep mentioning years ????--- 64. My '64 GTO came with the new style of rearend--- a small 10 bolt. I don't know what was under the other Pontiacs in '64 but the GTO's did not have the same style strong chunk style rearend as the earlier Pontiacs.

 

Only full size cars got them, not " A" bodies...Your GTO is an 8.2 rear

 

For tech info and parts I found Brad at Fabcraft in TX was real helpful and has most parts including posi units. They were able to identify what we had and were great to work with. ( www.fabcraftmetalworks.com)

 

anyone translate these # L123 643317 olds rear

 

So I just bought 2 units this weekend and thought I was getting a 1950 and a 1955 Olds? They look similar but one is slightly bigger and the 3rd members won't interchange. So I have referenced the P/N's on the 3rd Members against this thread and it looks like the 1st unit is actually a 1947 era?

P/N 506925, This was held into the housing with regular hex bolts.
10-Spline Axles
P/N 516744, This was held into the housing via studs and hex nuts.
16-Spline Axles

From what I can tell by reading thru this thread, if I had indeed bought a '50 and a '55 the shit would have interchanged between them? Like the pumpkin should have easily dropped into either rear-end housing? This is not the case at all and I'm trying to clarify what I really have! The 516744 will not go into the smaller housing at all. Did they change in late '48~'49 to a slightly larger housing and then stay basically the same up thru '56? If so, does the early housings, '49~'50, look like the later '54~'56? I am using this for my Dragster project and want to make damn sure I've got the right one before I cut one of these things up... I would hate to slice up a rear-end only to not have it be the right one!!

Thanks much for all the info on the thread!

Cheers,

Robert M.

 

Lots of good info thanks

 

If your looking for rear end parts including brake stuff I have a guy in Chatsworth Ca. that can get just about any part new. Mike at Mobile Brake 818-439-7900 Give him a call, tell him that Robert Seghi sent you.
I just bought shoes, wheel cylinders and drums for a 1964 Olds. Pont. rear. NEW.

 

Late 1963 production. And that is what they call the late 9.3 inch. Believe it may have different pinion bearing than the earlier rear ends. Parts and info from Fabcraft -
800-208-8242 or www.fabcraftmetalworks.com

Dave

 

Side gears are the same through 64. 56 Pontiac yoke fits early rears. 56 uses same U joint as 57 up.

 

Fabcraft Metalworks has a new comprehensive book on the '57-64 Pontiac/Olds rear diff. available. It decisively answers all of the questions out there.

They're also offering new 31-spline side gears and spider gears for the Safe-T-Track units.

800-208-8242

 

How strong are the 55 - 56 olds rears?

 

The one on the left looks like 1949-56 Ford car.

Oops, I just noticed that post was from last year.

 

I got the following info from a guy selling a 3 rib Olds posi center section on the bay. I thought the mods shown in the pics might be worth posting in an effort to keep some of these old rears alive. They looked pretty well thought out and I hadn't heard of them before (I'm no expert). Any of you guys that really raced these rears ever heard of these changes with the bigger bolts and such?

The text below is right from the builder/seller:

“The Posi was beefed up with oversized bolts and the threads were tapped deeper, all the way through, for longer Allen bolts. The left cap is also drilled for 1/2 inch bolts that are tapped deeper than original, all shown in the pictures”.

 

been running olds/pont rear for hard street&strip duty for many!years...
summers bros spool axles 5.38 ..........

 

i have seen posi bolts brake where treads ends and longer 7/16 bolts gets into the 2-pice unit and add better strength.had an idea of studs instead but this will work.

 

I think I have one like the top picture...cam out from under my 36 Ford coupe parts car. Is the number that designates gear ratio a stamping or a casting? Where is it located? All I can can so far are these casting numbers:522496 , B 7 7(date I'm assuming), and a large 7 at approx. the 3 o'clock position.

 

I've got a '57 Olds Rear in my Model A and I'm looking for the third member gasket, does anyone know the part number?

 

This may have been brought up before, but here goes...
My '57 Chevy has a '57 pontiac rear axle with a 31 spline third member and stock axles from a '59-'64? rearend.
Upon inspection I could tell that the axles had a portion of their splines cut off. Evidently the later axles were a bit longer. The splines are now 1" long. So, I guess some 31 spline axles can be shortened and used in '57-'58 housings
While Im at it...
The car had an open differential (5.86 gears!) which I changed for a 3.08 open pumpkin and had no problems at all.
I traded my way into a 31 spline 3.91 posi and swapped it into the car. When I put the axles back in, the splined end bottomed out 1/2" before the bearings did. Not good.
I posted this on the board a few years back and got responses anywhere from "check the axle splines" to "there are 2 splined pieces to the side gear on a posi and the splines may not be lined up". I knew all these things checked out to be ok, so I went to the phone. After talking to a few people, I spoke to a gentleman who basically told me "yep, some posi's are like that, if your axles dont have enough spline length to shorten them, you will have to get aftermarket axles built.
Now I know.
Hope this helps somebody out...

 

The last gasket I ordered was from Car Quest Auto Parts. Part #P29325.
It was a Victor-Reinz gasket. The number was stamped on the plastic bag, but Im not sure if it was a Victor number or a Car Quest number?

 

I have some NOS Felpro or Victor boxed gaskets for 57 up, I will look tonight.

 

To all interested,Fabcraft Metalworks manufacturere of vintage racing/performance equipment has all kinds of parts for Old/Pont rearend assemblies.They are even making new posi units! Brad is a great guy and Sue is a sweetheart and very intelligent on all this kinda stuff as well! They have a new book out that covers just these rearends! It is on my Christmas list! Call Sue at Fabcraft tell her Redline sent ya! 1-800-208-8242

 

I just use non hardening permatex.No leaky!