I picked up this rear end off of a craigslist add. Its kind of a mystery piece very few numbers or familiar markings. I posted a photo of it awhile back and got some response just curious if someone may know more about it. The pan it sits in is a cool piece I do which I had a few more of those. Thanks for the help.

Clutch sure grip--that's GOOD. 3.73 gear apparently (never seen ratio stamped on the outside of the case). Great ratio if that's what it is. And a rare ratio.

The case is early too, andcool.

That has to be a late 50s, early 60s unit.
LOVE the Spicer diff too (Or is it made by Dana?). rebuilable forever as long as you don't crack the case!

Since it doesn't look like the holes for the pinion snubber were never drilled, I would say is from a truck or van (as would the gear if its original). A clutch sure grip would put it in the mid to late 60s, I believe. Gene

1958-1961.

It looks like a early pre 742 case, is there any readable casting numbers under the pinion gear on the drivers side?
I wouldn't run that unit at all until I took it apart and got rid of all the rust on the spider gears and everywhere else If you run it with the rust like that is on the spider gears it will be worn off and turn into a very abrasive substance that will kill all the other moving parts in that third member

Only number I could find on the case is 15349?. Gears inside are 323's

See the small diameter drain plug. Old ones have that. With a 68 date on the sure grip and 3.32's means it was redone after,the factory. That is a ratio stamp on it 3.73, they did that 61 and back. I have a 3.31 here.

Good info thanks guys!

That is a pre 1961 third member probally. I saw one like that years ago, 1964 to 1966, in a 1957 Plymouth Savoy flathead six cylinder car with 3.73 in it that had been flipped up on one side so someone could rob the tranny out of it behind a bowling alley in Yucca Valley, CA back then. I should have came back later after work and grabbed that rear end for future use Hindsight is always better than forsight, correct I put a set of 3.73 gears in a "741" case years ago to try in my old pump gas street Duster, that stupid car ran the same ET and MPH with 4.10, 3.91 and those 3.73