Hey. I was never a Ford man until a few years ago, now I own 3 of 'em.

I got me this here 2007 F250 SuperDuty, 4x4 extended cab with the long bed. Driving it on a bumpy road is like getting kicked in the kidneys, but I love this truck. Got a question for you experts:

I want to know if I can visually identify the rear differential when I change the grease and tell if it is a locker or limited-slip or whatever Ford calls it.

I figure a 4x4 ain't really 4WD without some kind of rear diff that don't have a certain amount of lockup to it. I figure this old work truck with 4.11:1 gears is probably equipped with a posi but I'd like your learned opinions.

As always, advice/insults/witty comments are welcome.

 

You don't even have to pull the rear cover. Just jack up the rear end, and make sure both tires are off the ground. Leave the transmission in park, and spin one of the tires. If you have a locker it won't spin. If you have a normal rear end the other side tire will spin in the opposit direction.

 

Find your data plate....


AXLE CODES:

37- 3.73

3L- 3.73 LS

41- 4.10

4N- 4.10 LS

43- 4.30

4L- 4.30 LS

48- 4.88

8L- 4.88 LS

53- 5.38

5L- 5.38 LS

 

You know Curtis, I think I sorta knew that, or I did 30 years ago.

'preciate it.

 

Interesting. I had to Google "data plate" but then I found it. Axle 3L, so it is geared taller than I thought, but it is limited-slip.

Happy happy.

Mucho garcias kind sir.

 

You can verify that by looking at the differential cover. There will be a metal tag with a bunch of numbers. The first numbers would be 3L73. That L is limited slip. If it was an open diff it would say 3 73. The L would be missing.