wanna put a locker in the rear diff and want to know how i can tell what ratio of gears i have. Can i do this without opening the rear end??

 

There is a sticker around the back axle that says what it has. Same for the front its 4x4. It is on the passenger side. (Mine was anyway)

 

If you have limited slip then you can jack one tire in the air leave the other on the ground. Put the truck in "N" and turn the tire 2 complete rotations while watching the yoke. Count the rotations of the yoke and you can get a good guess from there. 3 3/4 turns of the yoke would be 3.73 gears, a hair under 4 turns would be 3.92, 3 1/2 turns would be 3.56(?), .....You should kinda see the pattern. This works great if you know it has factory gears and you know what gears where available because you can guestimate the ratio. But if your dealing with aftermarket gears (especially ford where there are so many ratios available) it will only get you close unless you build some kind of dial and pointer, but then it would probably be easier to open the diff.

 

Man is this going to be hard. Get some old work clothes, gloves, hand cleaner and plenty of beer. See if you can get some friends to come over and help.
1. open passenger door.
2. open glove box.
3. read sticker in glove box.

If that proves too difficult, get your VIN and call the parts/service department at your local dealer.

 

thanx for the replies guys. Will check out the back axle for a sticker or in the glove box

 

What gears you thinking about getting?

 

My brothers 06 doesn't have a sticker in the glove box, but my 03 does.... I would look there first.

 

not sure, kinda want 4.10's cause im puttin 33's on this week. Figure it has 3.92's in it cause it has the 20" wheels and you can light them up instantly and those are like 32" tires