onelildude

I am really considering re-gearing my truck, but i'm hearing some pretty crazy things about doing so. First off i heard that going from my 3.55's to 4.56's would lower my mpg(from 14 to 10)??? also i am thinking of Roush Charging my truck in the future and i heard that gears would probably cause my truck to react in a crazy kind of way. So can anyone that has re-geared or has any knowledge of gears give me some input????

luckythirteen13

everything you heard is wrong. your mpgs will be affected by gears but not that drastically. depending on how you drive, your mpgs could even go up after the gear swap. yes the motor will be turning higher rpms with the gears but it will be under less load and it will get into the higher tranny gears faster which both help mpgs. truck weight, mph, how hard to hit the gas from a stop, towing or not, all these will effect mpgs.

as far as the supercharger goes, the gears and sc dont have any direct relationship with one another. lower gears plus more power means the truck will launch harder and have a lot more torque down low, right where you need it for towing. the truck wont act crazy or anything like that, you will need to be carefull in the snow or on wet surfaces tho with gears and a sc because too much throttle to fast will cause the tires to break loose. but again, its all in how you drive. i have a mustang with about 600rwhp and a set of 3.73 gears in it (stock is 2.73) i can drive it in any weather without issues if im smart about it. but even when it is hot and sunny (like it was when i took the car out today) i can punch it 2nd gear and just roast the tires, slam 3rd and keep the tires spinning till i let off the throttle. it gets sideways when i do it and makes more tire smoke then a john force burnout. if you drive smart youll be fine, if your retarded, be ready for a bad day.

you also want to keep in mind that our trucks are much longer and heavier then my mustang so you wont have to worry about getting sideways

f150mashin559

i have heard and experienced that when you have a longer vehicle it is kinda easier to get it sideways and control it better.

wxmcpo

Changing out my gears form the stock 3.55's to the Yukon 4.56's was definitely one of the best mods I made to my truck.

BlackSTX

I agree, swapping for a better ratio, especially if you increased tire size, may actually help your MPG.
Larger diameter tires makes your gear ratio "milder." Not that the ratio changes, but its made less effective by the larger tires. Swapping in a better ratio can restore the original performance or even enhance it.
Let's not forget, these trucks are heavy, and larger wheels are often heavier and more difficult to keep turning; gears may be the best move you can make.

blackbetty

if you upgrade gears, go with a quality kit, a quality cover, such as magtec, and go with a good shop, one who knows how to properly do the job, because if not done correctly, like most automotive work, you will be doing it again, soon.....

i am in a performance type truck build, and i am going from a 3.55ls to a 4.56 gear set, i have a 8.8 rear/8.8reverse cut front and 17inch stock rims with performance rubber, about .35-.4 inches smaller then stock. it should be way more then i need but it will help off the line numbers.

blackbetty

by the way, if you have a 4x2, you should pay around 5-700 where as a 4x4 could be anywhere from 950-1500 due to the front pumpkin being a pain in the ***.

onelildude

Thanks for clearing. That up for me, because I really want to regear for the power but also to get as close to stock, with 35s, as possible. So what's the reccomended gear 4.56 or 4.88???

luckythirteen13

4.56 will get your final gear ratio closer to stock with the 35's then 4.88 but with the extra weight of the 35's i would go with 4.88 the rpm difference is so little youll never notice it. i have 4.88s and i wish i would have done 5.13

91351

4.56s and a roush charger = a lot of donuts