Nharmswhey

I just got my truck back from the shop that lifted it and they suggested that i get new gears. Which beings my truck is a 4wd i would need both front and rear gears correct? So what size ratio should i go with and what are some signs that i should get new gears. I have a 04 fx4 with a 6in ProComp Stage 1 lift. With 35" tires on 18" rims. Thanks for any help

wxmcpo

I have a 6" lift with 35's on it and I went with Yukon 4.56 gears.

luckythirteen13

i went with 4.88s. the rpm difference between them and 4.56 is so small you cant tell the difference but the extra grunt off the line is nice. wish i went with 5.13s tho

Kevin O.

5.13's HOLY SH*T. i'm just going with 4.56's

luckythirteen13

it sounds like a big difference but if you do the math the rpm difference is minimal at best

NexTGeN

Yah I got 35" tires and a 6" Pro Comp lift.
If I got 4.56 gears would my gas mileage suffer?

wxmcpo

Gas mileage won't suffer, if anything you'll gain a little bit. What you'll regain most though is that lost power form lifting and adding larger tires.

wxmcpo

Gas mileage won't suffer, if anything you'll gain a little bit. What you'll regain most though is that lost power from lifting and adding larger tires.

NexTGeN

Mmmm, I see...
What is the stock gear ratio on my F-150?
05' FX4 5.4L V8 Extended Cab.

MHC-F150

You probably have either the 3:55ls or 3:73ls. I'd venture to guess the 3:73ls, but there should be a tag on the rear diff that explains what you have or it should also be on the door jam. Can't remember what it says and how to read it though.

I think your best option would be the 4:56. 4:10s wouldn't be worth the swap, 4:30s seem to be hard to find, and not sure if I'd go so aggressive as the 5:13s.