8 3/4 Differential Question

amazinblue82

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Couple questions? thanks in advance for any help

I have a 8 3/4 differential i found in my warehouse (yes, sad i don't label stuff).

1. "742" case, date stamp "7G12": what date is that?

2. its a 2.76 "Sure Grip" (47 teeth on ring (p/n 2070684), 17 teeth on pinion): IF any car had a sure grip option for a tall gear it would be a C body. Any such thing from the factory to anybody's knowledge?

3. an aside...the original case markings (white paint - "817" on other side, stripes on the bottom, even one stray mark showing about in lower right of top picture) were under the grease on the bare cast iron...that make sense?

i thought they were painted from factory -- no?

4. yes, i have the snubber too. it was greased up pretty good so its soaking.

5. 30-spline axles

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742 tells us it is a from a 440 car as 383 cars carried the 741, the 742 was replaced by the larger pinion 489 case in about 70 or 71. Maybe 69? Sure grip option was available to anyone who would pay for it. As for the white paint, that is the remains of production line markings put on the housing as the car was assembled.
 
Can we see a pic from the gear end? That will help us to work out if it is a cone style or clutch style sure grip center.
 
If that was a 2.97 S.G. I'd have been interested....nice find though.
 
Okay that is the more desirable clutch type sure grip as the clutches can still be purchased for them.
 
Okay that is the more desirable clutch type sure grip as the clutches can still be purchased for them.

thx for helping me. your expert confirmation is most appreciated.

any thoughts on date of this assy? my guess is 67 or 68 MY. but i cannot find "7G12" anywhere as dating convention for diff castings.

unless 7 is yr, G is month and 12 is day?
 
I'm not sure what the numbers stand for on that, but all I can say is it can only be for the years 1964 to 1969. The sure grip is, to be technical, supplied by Dana and was called a Power-Lok. A lot of guys here will latch onto that by the way, it actually has two names!
The last sure grip I put up for sale was the same as this but with a 3.23 gear in it and I sold it for $300 which took about 2 months to sell. Hope this helps.
 
There should be a date on the ring gear.
 
thx for additional insight.

price discussiions in the open forum always attract a variety of views here. then somebody wnds up insulted. :)

dunno what price should be so i just let the market sort it out on feebay usually

i try to study asking prices vs actual selling price, etc., plot them on a chart, a mentally draw a 45 degree "trend line" to see the most likely price ...which is where i see the "dot cocentration" closest to the line.

that becomes my price target. semi-scientific "swag" admittedly -- but data driven to extent possible.

on this one, i forgot i even had it - and its been at least 8 years. so if it takes a day or a year to sell i can wait or just use myself :)
 
Here's one I have laying around. Dated clearly...

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I like to be heloful when I can.
 
I like to be heloful when I can.
geez..:)

off topic -- i keep looking for signs i am becoming a "fogey". the inevitable decline of abilities with age, and then pretty soon after i am yelling "stay of my grass" to everybody I see -- even when I am not at home. i am starting to "miss" the obvious things more and more it seems

so back on topic: yes, matt, you are HELPful. AND the answer to my question is the RING date is August 8, 1967. on the Ring it shows as "8 8 67" widely spaced like your example. now my judgement is the case casting is dated July 12, 1967 - three weeks before the ring.

I have high confidence this piece was from a late 1967 or early 1968 model year car. All mysteries solved. Thanks everybody --- particularly Wollfen and detmatt.

Those of you who inquired about it privately, it'll be on ebay starting tonight...but PM me here at anytime if you decide you want it to get your 20% off (if you've been a member for at least 30 days) and I will end the auction.
 
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