How can I tell? I don't get a lot of wheel spin except in the rain, so it's not like it's obvious. Is there anything in the VIN that would tell me? By the way it's a 97 Super Cab 4x4 4.6 auto Lariat.

Thanks.

 

You should be able to feel it around a corner when it wet. If you feel a kinda jerky feeling, that's it working. If the inside tire just spins freely, you don't have it or it's totally worn out.

 

You'll be able to tell when you go around a turn and peel out. The rear end will sorta hop and jump around. I know, because mine does it

 

???? I've got limited slip and I don't get any "jerky" feeling or hopping around. If you want to use a "spin" method to check it, try in sand or lose dirt, or even a slick wet road but be careful if you decide to do it on a slick road.

I think on a slick wet road you'll know real quick if you have an open diff. With mine, LS just keeps me straight and solid on the ground.

 

Test for limited slip...jack up rear wheels and spin one wheel, if the other wheel turns the same direction, you have a locking rear end...If the other tire turns the opposite direction then you have an 'open' differential....

 

Hey!

It's very inconvenient that search option is disabled...
BTW, any words on whether is will come back????

Here is the list (from different F-150 site) of codes on the driver side door under REAR section. Look what matches to yours....

F-150:
19 – 3.55 Non-LS
18 – 3.08 Non-LS
H9 – 3.55 LS
B6 – 3.73 LS

F-250:
27 – 3.31 Non-LS
26 – 3.73 Non-LS

Ranger:
84 – 3.45 Non-LS
86 – 3.73 Non-LS
87 – 4.10 Non-LS
89 – 4.56 Non-LS
F6 – 3.73 LS
F7 – 4.10 LS
92 – 3.08 Non-LS
R5 – 3.55 LS
91 – 3.27 Non-LS
96 – 3.73 Non-LS
R6 – 3.73 LS

 

....or, be smart and ignore all the "sand" and "wet road" suggestions and look at the chart AB posted and see what you've got!

 

With a truck that old, you guys are assuming alot..If it is original then that will work....If it has lots of miles or is second hand you dont know whats in there now.....

The ratio is easy to figure out as well...turn the tires until 1 full revolution is made on the driveshaft ..these numbers form the ratio...