I have a 06 f150 screw with the 5.4L V8. I put 35x12.5 tires on it with 17" eagle alloys. i want to regear to some 4.10s to get my power back i had before the big tires. im thinking ford racing 4.10s? where is the best place to buy them at the best price? Also im not 100% sure if i have a limited slip differential or not, i think i do but i dont know for sure because i bought the truck used. Does anyone know if it came with a limited slip differential? if not what is the best one to buy to go with the 4.10s and where?

i really appreciate all the help!

-Tyler

 

LS was an option on your truck and also came with the 3.73s in the towing package. Do you know if your truck came with the towing package?

 

It came with the towing package and I know it has 3.73s I just don't know if it has a LSD

 

if you have 3.73's now, 4.10's won't impress you. go w/ 4.56.

 

I second that, 4.56s

 

Im pretty sure the 3.73s have a LS.

Look at the door sticker for your axel code. My trucks code is B6. 06 FX4 with 3.73's and LS.

4.10s I think will bring it close to how it was before the tires. 4.56s will give you a bit more umph.

 

Here's the problem with getting 4.56s, I drive over 50 miles round trip to get to work every day on the freeway so I will be running at higher rpms with that gear ratio and loosing more mpgs. Also I tow a trailer about 5000lbs every weekend will that be a problem with 4.56s? I do have an edge programmer to change the speedo etc. Do you guys still think I should go with 4.65s in my situation??

Lordfeyr: thanks for the code. I will check it out when I get off work

 

ive got 4.11 gears with 305/55/20s and my truck rolls fast and loud. only runnin 2000 rpms at 70 mph.

 

If you have 35" tires and you tow, get 4.56's. Your unloaded gas mileage won't suffer. At 70 mph, it will be running at 2150 rpm in overdrive.

 

That's not bad at all. I will go with 4.56s then. Where is the best place to buy them from?

 

yeah 4:56 FTW!

 

Use the ratio, original tire diameter/original gear ratio equals 35/gear to keep rpm the same.
In other words, new gear ratio to keep rpms the same =(35 x orig gear)/original tire dia.

 

Ford Racing Performance Parts are usually available at your local Ford dealer. You can also order them from Jegs.