Need Help Identifying Gear Ratio

[djkswiss]

Just bought a new truck, you can see details in my signature.

The rear differential cover looks a bit rusty and I will be replacing it and changing the fluid while I am at it.

The door jam does not have an axle code.



Here is are the two stamps, I need to know if I have a limited slip diff, because I believe I have to had friction modifier in the fluid if I do.





Thanks for looking!

[Fred Swanson]

3:73 limited slip if I am not mistaken....there is a 3 under the bolt head on the tag thats on the passenger side of the rear axle.....Fred