Hey guys, i am about to lift my 08 F150 with the rancho 4" lift and put 35s on it. I have heard that i should put 4.56 gears in it, how is this going to help my truck? (better mpg's?, faster?) and also what size are the gears? like in on my mustang it is 8.8 but i dont know what it is in my truck?

Thanks Guys!

 

the advantages of re gearing is less strain on the engine and transmission, better off the line performance, and may or may not help your mpg.

what engine do you have in the truck?

 

it is the 5.4

Thanks

 

then you have the 9.75 rear end. the 8.8 rear was for the 4.6 and V6 motors.

what kind of driving do you do? do you tow at all?

 

Get the gears. They make a world of difference. Even with heavier wheels and tires u still will pickup a tad on the seat of the pants feel over stock setup. I had an 02 with 315 70 17s and the gears made the truck I thought. I towed a lot and it made a huge difference. I used yukon gears not sure what r best but those worked real well for me.good luck!

 

Yep, the heavier wheels and tires will burden the engine and trans as they require more HP to spin up to speed just like bigger heavier flywheels so the gears will help as they simply multiply torque and 4.56 is a bigger multiplier than 3.55 or 3.73. Of course, it all will require more gas per mile which is less miles per gallon, and then you'll have to stop all that rolling mass which means you can look forwards to spending more quality time with your brakes.

Sounds like a fun package ....

 

I just do normal street driving, no off-roading. and i havnt and dont real plan on towing anything seeing is that i dont have anything to tow. so in the end the the mpgs will drop and my brakes will wear out faster? sounds awsome!! lol. But hey if i am going to lift the truck i guess i have to deal with it.

Thanks Guys!

 

My 4.56's with 35's actually helped my city mileage a bit, up about 1.5 mpg. If I slow down and run 60-65 instead of 70-75 on the interstate, I can still get into the 16's mpg.

As of now, I have my stock wheels back on the truck, and I need to recalculate my programmer.

 

jump n, that is good to hear that you get better gas milage in the city. Thats really only what i drive, dont do a whole lot of highway driving. what exactly do you need to program when you get bigger tires??

thanks!
Jeff

 

im guessing that the front is the same?

thanks!
Jeff

 

Front is 8.8 and you need reverse cut gears

 

City mileage went up when I changed to 4.56 gears, much better drivability and the transmission is so much happier. Feels like a whole new truck, definitely worth it.

Front diff is 8.8 reverse cut, and rear is 9.75.

 

since you dont tow much, i would just wait for the gears. hell, i drove my truck for 4 years with 3.55's and my 35's before regearing.

 

That's assuming you do both the gears and tires, or just tires, or just gears.

If you do the tires first, you'll see a good drop in mileage and increased brake wear and the trans wil work very hard and the truck will be like a dog.

If you then do the gears, you'll recoup some of the mileage and acceleration and your trans will thank you ... but not all as you are still doing more work moving the same truck and heavier wheel and tire packages even if gears return overall ratio.

You'll still wear the brakes more.

Nothing is free. With something, there is always a cost. I bought a $6 magazine tonight, didn't have to have it, but I wanted it.



I'm talking "real" miles per gallons, not those indicated by an incorrect odometer.

 

so i should just wait and have everything done at the same time? or get the tires installed and not wait to long to get the gears? so my gas milage will improve by maybe 1-2 mpg in the city from the way it is now (stock) with 35s and 3.56 gears?


Thanks Guys