john mann

Hello, i brought our 1969 olds 3.91 12 bolt limited slip to the rear end shop, long story short, he told me it needs a carrier, iam having a hard time finding one, i talked with Greg at supercars unlimited he has one there brand, the problem is i cant use my GM 3.91 ring and pinion with this carrier, so is there anybody out there that sells a really good carrier or even a complete kit, thanks for any responses, p/s is my gm carrier a 3 series ?? john..

11971four4two

I have a complete 31 spline rear with same ratio
sorry no extra 28 spline posi units

all the best
brian

joe_padavano

No one makes new replacement carriers for the Type O axle. You'll have to find a used 4-series anti-spin carrier.

Fun71

You could try contacting monzaz (Jim Mitschke) here on CO or at jdrace.com. He may be able to help you find what you need.

I am wondering why you would need a new carrier. Is the original broken, or ???

1970greensupreme

What rear do you have? An O type or Chevy 12 bolt. O type have 12 bolts, cover to housing but only use 10 bolts to secure the ring gear to the carrier.

john mann

to all !! joe greg at supercars unlimited has a carrier but i cant use my GM ring & pinion, according to the rear end builder the 5/16 bolt that holds the pin in ?? has let loose at one time and has mushroomed the carrier where it bolts in ?? i havent seen it yet, it has been repaired i just brought it in because i wanted it double checked before i put it in the car, he said what probably happened is the car had bad wheel hop that's what caused the implsion inside the rear end, he asked me what we would be doing with the car, it only gets out like 3 times a year and then 5 to 6 times to the track 1/4 mile he said knowing that i should replace the carrier then better safe than sorry !!

john mann

I was looking on ebay and found this carrier here is the item #


333073859778

Fun71

Correct. The "new" carriers are Ford 8.8 units that have been machined to fit into the O-Type housing and re-drilled for the O-Type ring gear bolt circle. It is effectively a "3 series" carrier for the original 3.08-3.23 factory gears and the aftermarket gears. The factory 3.42, 3.91, 4.33, etc use a "4 series" carrier, which no one reproduces.

Fun71

That is the Ford 8.8 carrier that I described above.
Look at the description and you'll see this note:

• Compatible Gear Ratios: (Factory 3.08-3.23) (Richmond 3.42-3.90)

john mann

WOW !! not for me then, that's right fun71 i just now see that !!! here is what iam going to do, tomorrow iam going to call the shop where its at and have him send me some pics so i can post them here, then if i need one ill post a wanted for one and give jim a call and tell him whats going on, thanks to everybody who responded for me on this rear end issue !! john..

Fun71

John be aware that there are two versions of carriers for the factory 3.91 gear sets. The early 1967-1968 version was a Heavy Duty (HD) that had 31 spline axle shafts, then the 1969-1970 version was the "regular' version with 28 spline axle shafts.
You need to verify which one you currently have to get the correct replacement.

Here's some info that Brian Trick posted a long time ago:

Here is a list of the posi units & what gears they will fit:

#673 = 2.56 & 2.78 ratios, 28 spline
#671 = 3.08 & 3.23 ratios, 28 spline
#588 = 3.42 & anything numerically higher, 28 spline
#672 = 3.42 & anything numerically higher, 31 spline
***The 31 spline axles were offered in late 67-68 OAI cars only.

john mann

got the pics, here they are !

monzaz

Well you will need a pinion cross shaft and at least one spider gear as the thing started to fuse to the shaft...WHICH means the posi was not probably holding tight enough and will need to be looked into also check all the clutches and reshim or replace with new.
That is what I can see so far.
Jim
JD

john mann

fun71 iam pretty sure this is still the ford one 8.8 ?? on ebay here is the number 333073819617 would this be ok ?? or shold i sit tight and wait for a #588 carrier to come along, john..

Fun71

Yes, that is the Ford 8.8 differential. It would work with the Richmond 3.90 gear set that is included in the kit, but not with your original GM gears. Your call on whether to wait on locating a 588 carrier or installing that kit. Maybe add up all the things you would need for each, then see which makes more sense from a monetary standpoint?

john mann

yes, i agree with you i still have the 331 in it now from a 66 chevelle, so for now i have listed a want ad on classic Oldsmobile for a 588 12 bolt carrier 28 spline, iam willing to wait it out, come fall if i don't get one, i may go with the 8.8 with the 3.90 that we have been talking about, not much for choices thanks a lot fun71 you have been a big help for me on this, also to everybody else, Jim, Ralph, brain, and Joe p. and the rest of the olds gang !!!

john mann

Jim, (monzaz) i just need to ask you, are the 12 bolt 31 spline axle bearings the same as the 12 bolt 28 spline axle bearings?? thanks john..

Fun71

No, they are not. The 31 spline bearings/races are larger diameter.

My data shows the following:

28 spline carrier bearing: LM501349, 2.890" OD race/LM501314

31 spline carrier bearing: LM603012, 3.061" OD race/LM603049

john mann

fun71 Ken, you sure a sharp on all this stuff !! i work in a machine shop so i get your drift on the sizes !! thanks so much AGAIN !!! john !!!!!!!!!!!!

monzaz

As I read this it really appears that John is asking about the AXLE BEARINGS not the CARRIER bearings... so the answer is:
Yes 1967-68 31 spline sealed axle bearings are the same as 1967-1969 28 spline axle sealed axle bearings 1970 rears were Oiled type bearings.

The 31 spline carrier bearings are larger same as 12 bolt chevy 3.061 saddle diamter and the 28 spline axle 12 bolt olds carrier bearings are standard 10 bolt 2.89 saddle diameter.

Hope that clears up the info on the questions for everyone.

Jim
J D Race

john mann

PERFECT !!! it sure does now i know, thanks to Kenneth & Jim for all the info that i needed and have learned, now off to the rear end shop tomorrow at least i will know what iam talking about, thanks again for everything, john...