Diff date codes?

[40Windsor]

So, I have two diffs. Plan to use the 489 with its gears and the suregrip out of the 742. I have to replace the pinion seal, so I will install the pinion shim kit and new bearings at the same time.
742 is possibly out of an Imperial. Came with surgrip and 2.76 gears. Date code is 7K25. No clue on what that equals to.
489 is probably out of a truck. Came with open diff and 3.55 gears. Date code is 2763. I think that means Oct 3, 1973. Am I right?

[John_Kunkel]

Welcome to the board.

K is the month code for October so your 742 is October 25, 1967. The 489 is the 276th day of 1973 so Oct.3 sounds right.

[40Windsor]

Ah. Dont know how I didnt figure that one out. Thanks.

[Alaskan_TA]

OE ring gears & pinions have dates stamped into them, look for those.

If the Sure-Grip in the 742 is the clutch type, there will be a date stamp in it also.

[40Windsor]

742 gears are long gone and suregrip is boxed up waiting for rebuild parts. Ill pull the 489 out of its storage bucket tomorrow when i get ready to cut the axles down to size.