Rear Axle housing Decode Help

[jim28607]

Any Help with this Number ? located front of passenger side axle tube.

Thank You,
Jim

[KurtS]

The format was used in the 70's. Probably a 10 bolt, right?

[jim28607]

 

The format was used in the 70's. Probably a 10 bolt, right?

  BOOOO, I hope not , but I will sure investigate

Thank you for your input
Jim

[bertfam]

I agree with Kurt, and will go further and state the axle was assembled on the 177th day of the year, at the Detroit Gear and Axle plant during the 2nd shift, but I'll darned if I can find any GM car that used an MC axle code!

Also, I can't tell from the picture, but is there something else stamped after the 2?

Ed

[rare396bronze]

1967-1969 Chevy truck 4.57 ratio. Got this out of a old Hollinder Interchange book from my old junk yard day's.

[cook_dw]

1967-1969 Chevy truck 4.57 ratio. Got this out of a old Hollinder Interchange book from my old junk yard day's.

[bertfam]

1967-1969 Chevy truck 4.57 ratio.

I know absolutely nothing about trucks, but did they use this format in 67-69? (ratio code - assembly plant - Julian date - shift)

Ed

[bcmiller]

Jim check the casting number on the center section. And post a pic of the rear cover if you can.

Yes MC was used for some trucks/vans in the late 60s.

Not sure about 67 or 69 but yes for 68.

http://www.gmpartswiki.com/getpage?pageid=21082

[1968 Z28]

Yes MC was used for some trucks/vans in the late 60s.

Not sure about 67 or 69 but yes for 68.

http://www.gmpartswiki.com/getpage?pageid=21082

It appears that in this chart the "MC" is assigned to a Series 30 (G30) heavy duty axle.

[Kelley W King]

I am thinking that G30 would be a 1 ton van?

[jim28607]

I've definitely got some research to do , I think the axle tubes have been changed because there is diff grease leaking from both sides at the third member!!!!
Car has really wide rear tires , so I'm thinking it's been narrowed.
More pics coming  and I am great full for your input

Jim

[bcmiller]

Yes MC was used for some trucks/vans in the late 60s.

Not sure about 67 or 69 but yes for 68.

http://www.gmpartswiki.com/getpage?pageid=21082

It appears that in this chart the "MC" is assigned to a Series 30 (G30) heavy duty axle.

If it's what I think it is, then yes.

[bcmiller]

I've definitely got some research to do , I think the axle tubes have been changed because there is diff grease leaking from both sides at the third member!!!!
Car has really wide rear tires , so I'm thinking it's been narrowed.
More pics coming  and I am great full for your input

Jim

Possible but extremely unlikely. No reason to change tubes and if they did that, new tubes would most like have been used. A quick look at the cover will tell us a lot.

[jim28607]

Jim check the casting number on the center section. And post a pic of the rear cover if you can.

Yes MC was used for some trucks/vans in the late 60s.

Not sure about 67 or 69 but yes for 68.

http://www.gmpartswiki.com/getpage?pageid=21082

  Here are pics of cover  and some numbers I found.

What is it?

Thanks All.
Jim

[bcmiller]

Well that appears to be a late 69 and 70 passenger car 12 bolt.

Is there a casting date in the webbing area at the edge of the center section? From the rear look at the upper drivers side. Might be something like H 10 9

Go to this link and scroll down for casting date location.

http://www.camaros.org/drivetrain.shtml#axle

Look close at that stamped MC again. Could it be CMC ? With the first C spaced over a little?

[jim28607]

Well that appears to be a late 69 and 70 passenger car 12 bolt.

Is there a casting date in the webbing area at the edge of the center section? From the rear look at the upper drivers side. Might be something like H 10 9

Go to this link and scroll down for casting date location.

http://www.camaros.org/drivetrain.shtml#axle

Look close at that stamped MC again. Could it be CMC ? With the first C spaced over a little?

  Thanks Bryon

[bcmiller]

But, we still don't know exactly what it was from. The code on the tube doesn't seem to make sense relative to the center casting.

[cook_dw]

Frankenstein diff.. 

[jim28607]

It appears that I have a mutt for a diff, so what would one pay for a nicely redone 69 date code 12 bolt pos , non # rearend ?

[Kelley W King]

I met a guy at the Raleigh NC show sometime back who had several 12 bolts advertised as Camaro rearends. They were noticeablely modified. He said he took full size car 12 bolts and narrowed them and changed the spring perches. He was asking $1500.00 but he clearly did not try to match the welding. We needed one but passed on his. Found a real one rebuilt 410 posi and I think we paid $1200.00 but was really nice.

[ko-lek-tor]

It appears that I have a mutt for a diff, so what would one pay for a nicely redone 69 date code 12 bolt posi , non # rear end ?

You will have to do more research to determine value. You would have to provide the following to get a value: Spring perch-multi leaf or mono?  Posi unit-Does it have one? factory?- aftermarket? 3 series? 4? what gear ratio?
I sold a single track, 3.08 12 bolt for a Chevelle for $300. Camaros generally fetch more (perhaps 3X) for an equivalent.

[bcmiller]

I met a guy at the Raleigh NC show sometime back who had several 12 bolts advertised as Camaro rearends. They were noticeablely modified. He said he took full size car 12 bolts and narrowed them and changed the spring perches. He was asking $1500.00 but he clearly did not try to match the welding. We needed one but passed on his. Found a real one rebuilt 410 posi and I think we paid $1200.00 but was really nice.

Then you got an EXCELLENT deal if you paid $1200.

[bcmiller]

It appears that I have a mutt for a diff, so what would one pay for a nicely redone 69 date code 12 bolt pos , non # rearend ?

Honestly if it's a posi with a gear ratio that will work for you, I wouldn't worry about it. If it is functionally good for your needs, don't worry about the "numbers" at this point.

It is possible that it's a modified 1970 Impala rear, but without the casting date I don't think we can say for sure.

Price for a replacement will depend on what you want, but the engine and trans aren't original either - correct?

[jim28607]

It appears that I have a mutt for a diff, so what would one pay for a nicely redone 69 date code 12 bolt pos , non # rearend ?

Honestly if it's a posi with a gear ratio that will work for you, I wouldn't worry about it. If it is functionally good for your needs, don't worry about the "numbers" at this point.

It is possible that it's a modified 1970 Impala rear, but without the casting date I don't think we can say for sure.

Price for a replacement will depend on what you want, but the engine and trans aren't original either - correct?

Engine is  not for certain , and at this point probably not trans either . So I do agree why bother , but we just love to tinker with these things , so I'm always looking for something to improve .

[JKZ27]

http://www.moserengineering.com/complete-rear-end-assemblies/12-bolt-moser-complete-bolt-in-assembly/12-bolt-built-to-order-rear-end-package.html
Build it how you want it or,
I see "rebuilt" complete assemblies for $1800 and up. You never know who "rebuilds" them and what parts are used.
I paid $1000 for mine(69 3.08 coded) and replaced all the bearings with timkens, changed the gears so I now have about $1500 in it, discounting my labor. And, I eventually put new Moser axles in it.

[bcmiller]

It appears that I have a mutt for a diff, so what would one pay for a nicely redone 69 date code 12 bolt pos , non # rearend ?

Honestly if it's a posi with a gear ratio that will work for you, I wouldn't worry about it. If it is functionally good for your needs, don't worry about the "numbers" at this point.

It is possible that it's a modified 1970 Impala rear, but without the casting date I don't think we can say for sure.

Price for a replacement will depend on what you want, but the engine and trans aren't original either - correct?

Engine is  not for certain , and at this point probably not trans either . So I do agree why bother , but we just love to tinker with these things , so I'm always looking for something to improve .

Well my engine and transmission are not original to the car either.  Engine is a 1974 454 from a truck.  Bottom end is over built, to hopefully last forever.  4 bolt main block with forged crank, forged pistons and good aftermarket rods, cam is close to LS6 specs.  Transmission is a 1968 M21, but from a Chevelle.  Rear axle housing is original to the car, but none of the "guts" are (different posi, gears, aftermarket axles).

So, you are not alone. Many cars don't have the original drive train, for whatever reason.  The main thing is to enjoy these cars and enjoy life.  I love the "numbers" but when it gets right down to it, that doesn't make the car drive any better.