# rear differential ID



## mcyphert (Jul 25, 2015)

Hi. I'm a newbie to this forum and I'm sure this type of question has been asked a thousand times, but I'm going to do it again.... I've got a 10 bolt posi B-O-P that I'd like to find out what it is out of. The only numbers discernible is the casting number on the bottom right ear of the housing. The number (I think) is 9782977. Can this tell me anything?
Thanks for the help.


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## GotTogO (Jul 25, 2013)

Did you Google it?


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## Pinion head (Jan 3, 2015)

I just chunked a bare gray iron Pontiac 8.2 housing with the "977" casting. The housing came out of a '66 Sprint 6 LeMans and was rust pocked, or I'd have kept it in one of the racks.


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## mcyphert (Jul 25, 2015)

GotTogO said:


> Did you Google it?


Google wasn't any help....


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## GotTogO (Jul 25, 2013)

It's always worth a shot.


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## deanhickey (Apr 6, 2015)

What year is the axel? In 1968 the ID number was moved to the left hand axel tube. there may still be a sticker on the lefthand rear brake drum. there was also stamping machine breakdown in 67 where the stamp was moved to top of the left hand axel tube. Hope this helps and good luck. i would recommend getting a copy of gto restoration guide by Paul Zazarine andChuck Roberts. That is where i was able to get this information.


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## Pinion head (Jan 3, 2015)

The gray iron housing 9792977 was built with axle tubes and is either late '66 model use, or '67 model use. This particular center housing casting number was even used on housings for lower performance '67 Firebirds.


With the stamped assembly codes being tough to read, the easist way to identify which model year application is to look at the coil spring perches. 

-Is the perch flat with a hole in the center, and take a stamped steel "ear" shaped piece to bolt the coil spring down, if so, with that casting number, late '66 usage.

-OR does the top of the coil spring perch flare up 1/2", with a locator ring being a part of the perch? If so, the rear was used in a '67 or extremely early '68 Pontiac, or possibly, a '67 Buick A-body.


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## mcyphert (Jul 25, 2015)

Thanks guys. This will definitely give me something to go on.


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