Hey Guys,

I serviced the rear differential and was curious about the tag numbers.

Here they are:

S 409 B

3 L73 105 8B03

Any insite would be appreciated. The other tag reads 75W-140 synthic oil only.

Jeff

 

3L73 105 = 3.73 limited slip 10.5" Ford Rearend.

 

Hi Ken,
Thanks for the info and reply. I read that you installed the 2nd Gen Frx mod. What was the most noticable difference after you installed?
I'm thinking of installing one as my next mod. I have installed the 6637 filter and oil tube crossover. From those two mods the engine is smoother and the fuel mileage increased.

Thanks Again,
Jeff

 

With the FRx you will notice the cackle goes away. It is designed to purge the air that can be introduced into the fuel system a return path to the tank. The stock system forces it through the injectors, which can damage them. It is a very nice system and is the lowest cost for a regulated return that you will find, that makes it a hit to me.

 

Here's an example from my truck on how to decode the diff tag.

The codes on my rear differential tag are:

S409B
3L73 102 8C11

The break down of these codes:

S409B:

S = Sterling Differential

409 = Print Number (Model Number)

B = Revision Identifier (Change in Design)

3L73:

3L73 = 3.73 Ratio

L = Limited Slip

Absence of L = Open Differential.

102 denotes the ring gear size. 10.25 inches. 105 would be a 10.5 inch ring gear.

8C11 is the build date.

8 = year of manufacture. In this case it means 1998.
C = month of manufacture. A= January, L= December so C= March
11 = day of manufacture. So My differential was manufactured on March 11, 1998

 

Nice Job Robin!

 

Thanks Ken.

As far as I can tell I first posted that in April, 2008.

 

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