I have a 2003 F-150 Supercrew King Ranch 4x4 with the 5.4L Triton and it has a 3 inch body lift with 35x12.50 mud tires. My truck still has the stock 3.73 gears in it and its alittle slow. So what gears should i get so that it will be not as slow but will still do good in the mud?

Thanks,
Paul

 

Are you sure you have 3.73s?
My 03 came with 3.55s,,but it's not a king ranch.

With 35s you should have at least a 4.56 gear in there.
Depending on your driving habits maybe even a 4.88.

Phil

 

4.56 or 4.88

 

I agree with the above posts. If you are planning on going bigger latter on then you probably will want to go with the 4.88's. If you are not planning on going any bigger, then 4.56's will be more then sufficient.

 

I just put 4.56's in mine and I also have 35's. It is a huge improvement off the line and if I don't floor it playing all the time, I've seen a 2mpg increase in mileage. Luckily I live in a place that I don't have to do a lot of interstate driving at 75 mph because that's where it starts to hurt, running at 2600 rpms at 80 miles an hour. Overall, the best mod I have.

 

where is the best place to get the gears? I just got my 35's on, and later this fall I want to step up my 3.55LS to 4.56.

 

Sorry to hijack this thread, but i was wondering if i need to change gears when install my 305/65/18 BFG AT's? I have the 3.55 in it now. The tires are about 33.7 inches and i've been hearing that i'd be fine with my stock gears. But also i have heard the opposite, so i'm just no sure.

 

How big of a ring pinion and teeth should i get?

Thanks,
Paul

 

I haven't driven a new body style F-150 yet, but you should be fine. I had 305/70R17's on my F-150 that had 40 hp and 15 ft/lbs less than yours and didn't have many issues.

Don't plan on having the acceleration you had when you had the smaller tires on! Gas mileage might be lower as well, due to the engine needing to do more work to move. Regearing will help bring the acceleration back to or even better than stock.

I just put 285/75R16's on my 2k Expy (had 255/70R16's stock), and I'm almost better off leaving it out of overdrive until I go faster than 55 MPH if I am doing any sort of hill. I'm sure a tune would help me out a little (I'm going to need one anyways), but ultimately gears will be the better buy.

 

The 5.4 will have a 9.75 rear diff and you'll need 8.8 revers cut gears for the front.

Phil