Help with casting number 393820

Steve
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Help with casting number 393820

Postby Steve » Mon Jun 15, 2009 8:36 pm

I have a 12 bolt axle housing that I got from the junkyard. It is only the housing nothing inside at all. I can not find a date code. The casting number is 393820, also cast into it is CFD, DE, SC, 35, 180 and a big M 2" tall on the top of the pumpkin. The flanges are at the end of the tube 55.25" apart. I don't know what bearings, carrier, axles, axle keepers and brakes I can run. Any help would be appreciated.

Steve

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monzaz
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Re: Help with casting number 393820

Postby monzaz » Fri Jun 19, 2009 12:45 pm

Pictures will be MOST helpful.

From your descriptive parts and numbers I am going to say you have a OLDS 12 bolt rear and is NOT a try 12 bolt rear and will require gobs of money to rebuild. The carrier ring gear bolt count is 10 bolt not 12 bolt as a chevy 12 bolt which actually matches the cover bolt count.

Posi unit are VERY hard to find and will be in the 500.00 range for aftermarket units. Gear sets are limited to 3.42 and 3.91 and will only fit the 3 series carrier (3.08 3.23 ratio carrier)

Axles will be easy to find as you can use them from any 10 bolt 8.2 pontiac olds or buick. from 1965-1970 But you will need to know if you have sealed bearings or non sealed bearing axles. AGAIN pictures of the axle and axle end inside the tube will help us ID it for you. Jim
J D Race

Steve
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Joined: Thu Jun 04, 2009 7:52 pm

Re: Help with casting number 393820

Postby Steve » Sat Jun 20, 2009 4:32 pm

Thanks for the help. I took some pictures and found seals still in the axle tubes and found a number after wiping off the dirt of 9775113 on one. I got this axle to replace my 10 bolt in my 68 chevelle thinking it was stronger. Should I stay with my old 10 bolt?

Thanks for helping. Steve
Attachments
12 bolt 007.jpg
12 bolt 006.jpg
12 bolt 005.jpg

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monzaz
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Re: Help with casting number 393820

Postby monzaz » Sun Jun 21, 2009 2:20 pm

OLDSMOBILE 12 bolt 'O' type. Not chevy 12 bolt.

Going to be pretty expensive for parts and is basically a 10 bolt rear...A bigger 10 bolt rear but still 10 bolt. Jim

As for staying with it or the ten bolt??? The 10 bolt will be cheaper to build and if you are just street bound will more than do the job as long as who ever is building pays attention to all the specs needed.

you only get 2 gear choices 3.42 or 3.91 that is it for new gears.

All aftermarket posi units use the FORD 8.8 modified to fit the 12 bolt olds housing.

Bearings are easy to get. Jim
J D Race


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