where do i fill my 12 bolt?

year · Posted: Sun Aug 31, 2008 4:57 pm Post subject: where do i fill my 12 bolt?

I have had some difficulty finding where I can fill my 12 bolt. There is no plug on the cover, and the one hole that is threaded on top i believe is a break line mount. I have a 1968, however I believe the axle is from a later model because it has spring perches for the coils. thanks.
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front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option

CANTED · Posted: Sun Aug 31, 2008 5:48 pm Post subject: fill plug

The fill plug is on the right side in front of the axle tube. Just above the web that runs along the side. It's about a 1/2npt pipe plug of there abouts.
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Jim
70 ElCamino 461 solid M20 331eaton
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year · Posted: Sun Aug 31, 2008 9:11 pm Post subject:

Thank you Canted. It was right where you said it would be. I just had to scrape a little to see the plug. Its amazing what 20+ years of grease and grime can look like...
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front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option

year · Posted: Fri Sep 05, 2008 9:22 am Post subject: ring gear

Now I am having difficulty finding which size my diff is. "both" of the gaskets at Advance Auto didn't fit. Does anyone know how I can check? I can get the serial #'s later if that helps.
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front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option

bigjames4xl · Posted: Fri Sep 05, 2008 12:16 pm Post subject:

????

Only one size 12 bolt passenger size rear for Chevys, there is a 12 bolt oldsmobile rear that has a 10 bolt ring gear though. There's also a 12 bolt truck rear, that's NOT the one you need.

I'm assuming you're talking about a 68 year model
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Ol Paint and me

454/700R4/3.31 posi
8.30 @ 82.23 / 60ft @ 1.82
AND
14.5 mpg average on HRPT 2006

year · Posted: Fri Sep 05, 2008 1:07 pm Post subject:

I was told by somebody that the axle didn't have raised spring perches in 1968, which mine has. I have have been misslead on that. I believe I tried gaskets for 8.2 and 8.795 ring gear sizes, both for a 12 bolt. I'm considering cutting my own gasket pretty soon too.
_________________
front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option

bigjames4xl · Posted: Fri Sep 05, 2008 1:57 pm Post subject:

8.2 and 8.5 size gaskets are 10 bolt

8.875 is a 12 bolt

8.795?????

here's a good ID chart for gaskets
http://www.kennysrodshop.com/fab/how2/differential.html
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Ol Paint and me

454/700R4/3.31 posi
8.30 @ 82.23 / 60ft @ 1.82
AND
14.5 mpg average on HRPT 2006

year · Posted: Fri Sep 05, 2008 3:02 pm Post subject:

Big James XXXXL your correct about the 8.875, my bad.

Thanks for the chart. I'll get to the bottom of this, and I have a suspicion Advance had thier gaskets tagged wrong. Maybe pep-boys will have it...

p.s. how was power tour?
_________________
front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option

year · Posted: Tue Sep 09, 2008 3:58 pm Post subject:

Now I'm 90% sure that my axle came from an Oldsmobile. It is a different 12 bolt pattern, no dimple on the cover, and would just be too easy for it to be a real 12 bolt. I plan on keeping it untill I can break it, and then I would like to get a 9 inch for the added strength, and I think I can do it for cheaper then a 12 bolt. maybe somebody knows if going with currie or moser will make a difference, or has one lying around...
_________________
front willwood big brake kit
Edelbrock IAS shocks
Flowmaster 40 series
rear tire melting option