I have a 9 inch rear differential and I was wondering if someone could tell me the gear ratio from these numbers I found on the tag.
WFE-52 6DD 3L50 9 380D. I was not sure if they were D's or 0's. Any idea what the gear ratio could be.
Thanks

 

3.50 gear ratio, I beleive the L stands for limited slip

 

Gear ratio is easy: The "3L50" portion tells us 3.50 : 1, and the "L" means limited slip.

WFE-52--closest I can find in my secret decoder ring is WFE-E2, so recheck.

WFE-E2 is 3.50, limited slip, 31 spline, and shows F100-150 '73 to '79.

"6DD" is the date code: "6" for 1976, "D" for 4th month and "D" for 4th week of that month, if I'm reading it correctly.

"380D" is probably the plant code, and I don't have a decoder ring for those.

 

Thanks for the answers. How would this gear ratio be in a 73 f100 2wd with a 302. Not used for anything intense just driving around. would it be better down the highway than 3.00 gears

 

What are you looking for out of this? Are you wanting to get better gas milage? The 3.00 will give you a little better gas milage. But dropping to the 3.00 will take slightly away from you off the line speed.

 

well the truck has 3.00 gears in it now. I guess im just wondering if when going down the highway it wont be at such a high rpm. Gas mileage is never great with these trucks anyways.

 

You lose top end with the 3.50, but you gain off-the-line grunt.

 

A 3.0 with 28 inch tires is a good combo compared to 3.50 gears and a 31 inch tire. Just depends on what you want and where do you want to go.

Either way, it's an easy swap, just some silicone and some wrenches if you don't like what happened.

 

What would you guys use if you had this set up.

 

Like I said, it depends on the tires really.

Stock tires are around 28-29 inches which turns about 2700/2800 with an automatic on the highway @ 75 MPH

31" tires with the 3.50 gears will be around 2900/3000 @ 75

Pretty comparable. However, 28" tires and 3.50 gears will start buzzing 3200/3300 RPM @ 75 MPH

So, is the truck mainly 50 MPH+ or 45 MPH and less?

 

Well mainly 60 but I have 32 inch tires on the back. Which ill compare to your 31 inch at 3000... i guess.
So I think im goin to throw in the 3.50 rear an do away with the 3.00 if i dont like it ill switch back but i think it will be better.
Thanks for the help

 

Definately 3.50 gears with 32 inch tires.

If I were to do a long distance trip without any mountain passes, I would throw the 3.00 gears on there to save gas and wear and tear.

3.50 gears @ 60 MPH with 32 inch tires is 2200 RPM, very nice!

 

what is 2.75 gears @ 62 MPH with 27s in front and 29s in back......3 speed manual? does it make a difference the different size tires?

 

Thanks for all the help identifying this rear and thanks for the input on 3.50 vs. 3.00 gears.

 

29 inch tires with 2.75 gear @ 62 MPH = 1975 RPM

Formula:

Intended MPH X Gear Ratio
______________________ X 336 = RPM
TIRE SIZE