I want a new gear ratio in the rear end of my truck.. I have the 5.4 with 3.55 LS, I want a 4.10 rear... Can I do this just by replacing the ring and pinion?
If so... what size is the rear end. 8.8"? Will this work?

Any help is much appreciated.

Thx, Keith in Kentucky

 

I have the same setup in my xlt. The performance shop that I deal with want's to put in 4.56 gears from PRECISION GEARS due to the fact that I am running 35's.Before I do that I am going to talk to Ford to see how much 4.10 ring and pinions are for the front and rear. If I can get those for a resonable price I dont see any reasone why it could not be done. If I get a chance to talk to Ford I will let you know. If you find anything out please let me know.

 

It is advised you get the master bearing kit too, and if you dont know what you are doing your rear end is going to make a bit of noise.

 

From my buddy who owns a Ford dealership and is quite handy with a wrench as he races for Ford.

"I talked to our lead tech at the dealership. He said there is no problems
with swapping gears but you will need to get your truck recalibrated. He

said this fixes the speed sensors and the abs sensor problems that you will

run in to. His email is ...if you have any other

questions and his name is ... Let me know if there is anything else."


I am going with 4.56s as it will tow better, accelerate better and be more fun to drive...also going to 315/70s for tires.

 

OK so I just got a call from him again and he said its a NO GO. He put his truck on the computer and tried to recalibrate to double check for me and he said the biggest the computer would allow for on his(FX4) truck was 3.73... and went on to say if his techs couldnt do it, probably all Ford shops couldnt do it.

I asked how they did their race truck(04 FX4) which use 4.56s and he said that the computers are sent back to michigan and reflashed.


So it looks like you are going to have to wait for a tuner to come out and hopefully it wont be like the Chevy tuners and still throw errors with the 4.56s.

Hopefully I can get one of these reflashed computers so I dont have to drop 200 bucks!

 

I just want a bigger gear in the back to have a bit more fun with the truck.... somthing that will rocket me into traffic a bit faster... 4.10 is the biggest I would go, and I dont see it being worth the money to get a 3.73..... I want 4.10.
I keep meaning to go to ford shop and ask them but I just havent got around to it.
Also, how much do you think the ford dealership would charge for the gear and install, and reflash..

 

The new superchips 1714 tuner for the 04 fords will allow you to make calibration changes for tires and gears all the way up to 4:56. Get the tuner and 4:56 gears will be an easy install. It also helps a ton with throttle response and power. The new tuners are now shipping from ****** performance.

 

Ford wont recalibrate for 4.10s at this time...the only way my buddies are getting it done on their race trucks is that they are sponsored by Ford and the computers come from Michigan...

I called ****** and the lady told me that it should have the same capabilities as the 1715 which means it will correct for up to 4.56s and up to 38 inch tires