The reason I ask is (and also has me very frustrated) is the fact that the differential is missing the sticker that says the code, along with my door jamb sticker. So im kinda out in the cold. The edge reports a 3.31 ratio. Problem is it has the limited slip rear differential, and items online I have found say that the 3.31 is not available with a LS. Only 3.55 and 3.73. So is there anyway of figuring this out?

 

No, it does not. You must enter your gears. It has a default gear which may or may not be what you have.

You have to count drive shaft revolutions for each full turn of a wheel.

 

I have 3.55's, Evo default was 3.73. It's best just to check, even if you have 3.73, just to be safe and allow all the PIDs to be accurate.

 

I wonder if you couldn't do a sort of "end around" on this. Enter your tire size using Edge's chart and reduce it by 3% for "squish". Accept whatever gear ratio the Edge has for now.

Take it out on the highway, preferably an interstate and drive it at least 10 miles (by mileage markers) and see what your odometer reads. Alternatively, use a GPS and see if your speed on the Edge is "close" to what the GPS says.

If you see a fairly large difference, you've got the wrong gear ratio. Change it and repeat - making sure you've still got the same tire size setting as before (the Edge sort of trys to "change" this each time you reprogram).

This is what I would do if I was in your position.

Of course, a dealership could probably tell you the gear ratio too, if you trust them and if they know what they're doing.

- Jack

 

Call the dealer, have them run your VIN number, they'll be able to tell you.

 

Thumper, I wonder. I looked at my VIN code and there's nothing in it that tells me the gear ratio. But, I suppose if they have the VIN, they might be able to "trace" it all the way back to the assembly plant and even find out who did the final QC inspection!

- Jack

 

Correct, I didn't mean that there is a way to decipher the gear ratio within the VIN number. But they'll be able to figure it out in their system.

 

Just so you are aware, I plan to correct the gear ratio and tire size issues that are currently bothering everyone. When the Gryphon boots up, it will read the factory values located in the VID block and then use those as a basis for the modifications. This will eliminate all the confusion of what the factory values are.

 

What about those of us that have after market wheel and tire combos?

 

I'm sure you'll still be able to enter in your gear size and tire size manually.

 

Configure it yourself?
Just Kidding man.
Here is a link to a calculator that can help you out.

http://www.differentials.com/calc.html

 

If you still need to know - give me your VIN and I can tell you exactly what you have for gears, lsd or non-lsd, etc. etc.

 

So the F150 stock gear ratio is 3.55 correct?
I just crawled under my truck (2006 SCREW) and looked at the rear axle and it has a tab(s) on there that says it has 3.73....I had no idea
Here's where its located if anyone is interested in knowing what gears they have.
Mine was located on the rear of the axle to the right, unlike the picture and there was two of them, one with the recommended oil type and the other had the gear ratio

 

There are at least 3 stock ratios, 3.55, 3.73, and 4.10. Just depends on how yours was built.

 

Here a picture of my rear axle with a red arrow pointing to the tab with my gear size.