raw442

I've got a 1969 442 and I had to put a different driver's side axle in the rear end. Are there any size/spline difference between a 69 442 factory rear end and a 68 Cutlass rear end?

rocketboy

i have been told that some 68,69 4-speed 442s got the bigger axles i belive 31 spline.

droldsmorland

raw....Was your car made in USA or Canada? Canada cars got the 12bolt Chevy which has plenty of parts support. If USA its an O type which has limited support. I dont entirely understand your Q..."I had to put a different driver's side axle in the rear end". If so you'd already know the answer. I think you mean I have to put in new axle? Did you smoke the bearing on to the shaft? Again is it an O style or Chevy?
8.2 parts wont inter-change with either the Olds 8.5 or the Chev 8.8

If you do one side replace the bearings on both regardless of which rear. On the "sealed" O style axles I pop the inner seal out of the bearing and run the rear end fluid just a touch overfull with synthetic. Stay clear of Offshore junk bearings.

raw442

Sorry for the confusion. My car was completely missing the driver's side axle. the passenger side was there but out of the housing. I had access to the Cutlass axle but I did notice a difference in the housings. The 442 was much beefier than the cutlass of course. My car was originally an automatic built in Lansing, MI. I know I will be completely rebuilding the rear end (I'm pretty sure I shoved a mouse nest in the gears while putting the axle in). My question is will the Cutlass axle be equal to the 442 axle. I'll know for certain when I pull them both out and have them side by side, but I kinda want to know if I need to be looking for a better axle ahead of time. Thanks for any advice and knowledge you may inform me with.

rcorrigan5

A Cutlass axle should be equal to the 4-4-2 axle in an "O" type differential, the "O" type being what originally came in Lansing cars. The difference in axles will come in what the gear ratio is. If the differential is anywhere from a 2.56:1 to a 3.23:1 ratio, the axle will be a 28-spline. If it's a 3.42:1 or up ratio, it will have a 31-spline axle.

The differential ratio (and whether it's a one-legger or anti-spin and/or the car came with disc brakes) will be identified by a 2-letter or a letter-number code stamped into the passenger side axle housing, facing either aft or forward, sometimes upside down.

Or, at least, that's the way I remember it!

Randy C.

raw442

Thanks for the info! I'll jack the car up this week (gotta work a lot of O/T this week) and crawl under to see.

droptopron

if you are not sure if the axle is original note that in '70 the Type O axle has a slight taper to it and requires a different bearing.

droldsmorland

The short answer is if both are O type 8.5" ring gear axles they will be the same, or should be. Again an 8.2" is a lighter duty rear and will not interchange. Hard to tell sight unseen. Post some pics. No tellin what been messed with since new.
Now for what Randy said; That fact I was unaware of. I thought an 8.5 O was an 8.5 regardless of ratio? So 3:42 & up used larger axles? How do you know that and where did ya find that info. I serviced a higher 3 series axle a while ago and didnt see a difference but I wasn’t looking for it?
Randy please elaborate. Never done learning!

JIM'S w30

1967-68 w30 cars and some 1968 4 speed cars only got the 31 spline axle the 1969 cars never had the option and never got 31 spline they only got 28 spline axles

pcard

I have attached a compilation of information on "O" axles which may be helpful, gleaned from various sources. Please excuse me if I do not cite ther references, I did not record them at the time. I hope that those sources will understand.
Note that I do not think this information is complete by any means. For example, I just learned recently that you can put a 3.08 gear set in a 2 series carrier with the use of special shims.
If anyone has any additional information please share.

rcorrigan5

I wish I could elaborate more on the 28-spline vs the 31-spline axles but my knowledge is based on what I had heard and how I interpreted what I read over the years. I don't have references, either. Makes me feel kind of dumb right now and it's clear to me that what I said is not entirely true. Jim had a comment that is consistent with what Supercars Unlimited booklet "4-4-2 By The Numbers" says. But pcard's axle document talks again about 28- and 31-spline axles for 1970. I'd like to see others chime in here on what they know.

Randy C.

507OLDS

The 31-spline O-axle rears were produced from late-67,to 1968 only,and were intended for OAI-equipped cars.However,there have been a few oddball cars that got a 31-spline rear installed in them,in 1968.
All of the other O-axle rears,from 67-70,including the other ones produced in 67/68,were 28-spline.

droldsmorland

Might as well discuss what made up a true W27. Was it a 10 or a 12 bolt carrier? What size was the ring gear? 8.5? Was it a "O" or a "corporate" axle with the aluminum center section? How many splines on the shafts?

507OLDS

The W27 rears are a 12-bolt O-axle,with a special cast aluminum center section.They have 28-spline axles.They use the same ring & pinion,and posi carrier that the other O-axles use.

droldsmorland

I was unaware Os came in 12 bolts, thought only 8.5 10 bolt. The 12 were Chevy right?

507OLDS

The 12-bolt O-axle has a 12-bolt cover and 10-bolt ring gear.
The 12-bolt Chevy has a 12-bolt cover and 12-bolt ring gear.

monzaz

WOW, A lot of OLD wrong info in that down load. PLEASE ask if you need the low down on the 12 bolt olds and what you can and can not do with it.

IE - 672 carrier CAN be used in a 28 spline housing, pinion spline is 27 NOT 12 - Just plenty of posi units now - we can make you axles shaft 28 or 31 or even retro fit Full spools in the rears.

I have parted out plenty of 12 bolt olds and all 69 and 70 rears have always had 28 spline axles no matter what the ratio and option on the car.

I still call this 12 bolt olds rear a 8.4 as it truly separates it from the 10 bolt 8.5 corporate rear that came out in 1971 -1987.

Take care, Jim
JD

pcard

Thanks Jim!

monzaz

Everyone has to remember most internet info is UNCHECKED for accuracy...It is usually self monitored by its own users. try to look up 2-3 sources before confirming that the subject is true or correct. JIm

pcard

But it was on Wikipedia!!

And that is why we always defer to you Jim.

Yellowstatue

'68 axles have a separate seal mounted in the housing and '69 axles have the seal as part of the bearing...both our '68, four speed, Oshawa built cars, have 31 spline axles...one is a 3:42 and the other is a 3:91. The other numerically lower axles have 28 splines...

507OLDS

1970 was the only year that the O-axle came with the outboard seal,and the roller bearing.The 67-69 have the inboard seal,with the sealed bearing.
Here's another fact: The 67-69 O-axles have right-hand threaded ring gear bolts.The 1970 O-axle has left-hand threaded ring gear bolts. So,if you ever swap gearsets,make sure you have the corresponding bolts.

monzaz

I will agree and disagree with that right hand left hand thread deal...BUT I would never pin it to a YEAR LIKE THAT. 1967 1968 FOR SURE right hand thread but AS PLANTS TRANSITION ANYTHING, anything can be in there for a bolt left or right IF they run out of the older ring and pinion they WILL use the new left hand thread ring and keep that line moving with out looking at a calander...lol. The 1969 year is scary for rear diff parts . It is like 1989-1990 in GM cars 28 spline axles and 1998 1999 in the 10 bolt 8.5 to 8.6 transition trucks too.

So again I say physically check, NEVER assume because the car is a certain year and the rear is suppose to be original that this is true.

It is a good guide to help for sure...

Jim
JD

507OLDS

So I should clarify that by 1970,they were left-hand thread.I've had a fair share of early-production 70 cars,built as early as August/69,and they had the lefties.
I simply go by what I have seen and dealt with,and make note.Once you see them over and over,you can make a common denominator.I don't pay too much attention to the internet facts.I make my own from experience.

Another another quirky note.I had one 71-72 8.5" 10-bolt,with the smaller vent hole.I owned this car,and have the paper work still.I ended up getting the rear back from it,in exchange for a rebuilt one.It had the 70-previous style vent,with the smaller hole.Every other one that I have ever had,came with the larger one.However,this wasn't a super-early production car.It was built in January/71,and delivered to the dealer in February/71,and the pumpkin had a julian date putting it in late-November/70.There were plenty of others built before that,and they cam with the larger hole.Why that one didn't,who knows.