I know this has been beat to death but I have just spent an Hour searching the forum for no direct answer. I have a 2002 f150 Screw 4x4 auto Trans, with the 5.4 with 3.55 gears. I have a super chips programmer, GOTTS mod, and soon Efans. The truck has a 5” RCX lift with 35” tires. I drive mostly around 55-60 MPH. I also pull a light weight 25’ camper. It weighs about 5,000- 5,200 lbs. I have pulled it on the flat highway and around the house with no problems but I am looking to pull it to the mountains this year. I have been planning on putting a 4.56 gear but I have read a few posts that say they are unhappy with the 4.56 w/ 35” tires. Some say it is great and some say it is to low. I will be doing some interstate driving also 75 MPH. what would you do in my place? 4.10 Or 4.56. Also have any of you been unsatisfied with the 4.56 with 35” tires.

 

I have 4.56's and 35's. Drove for two years on 3.55's, then to 4.56's last summer. I've only towed a couple 4 wheelers on a tandem axle car trailer. Towed great, get 14 to 16mpg consistently. I wouldn't do it any other way. Love the 4.56's

 

i would go with the 4.56's. the 4.56's at 60 will put you around 1700-1800 rpm's. you would definitely want the extra grunt of the bigger gears when you are going around the mountains!

but what do i know, im running 4.88's and 35's

 

That is what i thalt to i am just getting woried dont want to regrete spending $1,300 on the wrong thing. Str8t six how bad are the 4.88 with the 35"? what kind of fuel mileage you get before the super charger with those. hyw and city

 

my gears work fine for me. i dont ever go above 60mph where i live and that puts me right at 2k rpms at 60mph. i got around 12-13mpg with my setup. i dont really drive in the city so most of my drives are on country roads.