raw442

I've got a 12 bolt axle from a 1969 Cutlass. Will these axle's go straight into a 12 bolt from a 1969 442? I know the 442 axle has 4:10 gears and is posi, but I don't know the gears in the Cutlass axle, I know it is not posi though.

Please any answers will help, thanks!

Fun71

I'm a bit unsure of what you are asking.
Do you want to swap an axle shaft from the Cutlass rearend to the 442 rearend?
Or do you want to swap the entire rearend?

Either way, the parts should be interchangeable if they truly are both '69 rears. The '70 12 bolt used different bearings so its axle shafts will not interchange with the '67-'69 12 bolt rears.

Funkwagon455

They should have no problem swapping provided that they have the same spline count, 28 or 31. However, I am sure that one or both of the resident experts here can give you the hard answer. Jerk one axle out of your existing housing for absolute/definitive data for a good answer. Good luck

raw442

The axle in the 442 housing I am unsure if it is original. I know it is a 28 spline. I haven't checked anything on the cutlass rearend. I would have thought that 12 bolts would have had 30 spline axles. I'm wanting to just put axles in the 442 hiusing because it has the better geara and posi track.

66-3X2 442

69 12 bolt 'O' axles did not have 31 spline axles. You can use an axle shaft from a 66/67 'B or P' 8.2 10 bolt axle in a 66-69 'O' 12 bolt 28 spline rear axle as they are also 28 spline.

2blu442

Mike, what years did have the 31 spline axles? I've got a 1968 3.42 with the large splines and I haven't pulled the axles yet on a 1968 3.91, but I thought it would also be the large ones.


John

66-3X2 442

The 31 spline axles were used in 67 & 68. They came in rear axles with 3.42 & lower ratio gears. The 12 'O' axle actually started in 66,not 67 as some think.

2blu442

Thanks Mike!

John

raw442

Thanks for all the info guys! I thought they would work, but I wanted some other opinions.

67442nut

The 4:10 gears were in the Chevrolet 12 bolt that came in the Canadian-built 4-4-2's in '69.
I've never seen 4:10's in the 12 bolt Olds rear end.
You might want to make sure that's not a Chevy "C" clip type rear end.
If it is, the axles are not the same as the Olds 12-bolt.

Fun71

Good point about that gear ratio. Since Richmond Gear made 4.10 gears for the O-Type 12 bolt I thought that was what he was talking about.

raw442

I'll recount the gears. But I do know the axles bolt in. There are 4 bolts that hold the axle in behind the brake shield. Is there anywhere on the rear housing that would have some numbers I can look up?

Fun71

Yes, there is a code stamped into the top of the right tube near the vent, but it can be really hard to see. I had to use a wire wheel on these two in order to see the codes.

Also, the gears in the diff may not be the ones it came with from the factory 40+ years ago.

1970O-Type12boltcodelocation.jpg


196812bolt342HDopendiffTLcode.jpg