I have a 99 superduty supercab long bed 4x4 5.4L and 35" MT's. This thing is a turd to say the least. Im going to be regearing soon, and am trying to decide between 4.56's and 4.88's. This is basically a hunting truck that sees some mud, and a minor amount of street driving. This is by no means my DD. According to the math a 4.30 axle with 35's would be almost the same as the factory size tires and 3.73's. But I know Im loosing some drivetrain loss due to heavier tires, more friction (wider tires) and more wind resistance. Currently the truck is useless in overdrive. If it goes in, it will come right back out....to much load on the drivetrain. Do you guys think 4.56's will be enough or should I just go with the 4.88's and have a little more useable power?

 

For what you described the 4:88's will work best for the mud and tire combo - assuming the tires are like the BIG 35" (much wider than stock) If you do actually drive some on the street The 4:56's will be good too and may give a you a more usable 1st gear! Honestly, I don't see think you would see a real night and day difference between the two.

What gears do you have now?

 

currently the truck has 35" super swamper boggers and 3.73 gears. Its a true turd to drive right now. At 60mph Im at about 1400rpm in OD and it will kickout cuz it can not keep up with the load on the drivetrain.

 

Yeah - that's what I thought per your 'turd' acceleration...35" tires, 3:73's, and the ole 5.4 engine. Not the best combo IMHO. Either one of those gears will definately help in the pulling / acceleration factor.

 

I have a 98 F 150 4x4 , and i just purchased 4.56 for that beast, currently running 315/75/16 and i really do need those gears, it feels slugish. Good luck on you'res.