Hi, I need help with this. I am not totally sure what they are. From the Ford factory you can buy the rear axle in 3.31 or 3.55 for $50 dollars extra or 3.55 limited slip or even 3.73 limited slip. Can someone explain what the differences are? My particular application mainly acceleration and speed. I have no intention of towing anything, I just want it to accelerate fast and hit top speeds sooner. Eventually I will Roush it. My truck is a 2000 F150 XLT shortbed with 5.4 liter V8. Thanks for the help guys.

 

The axle ratio is the number of times the driveshaft spins around for each time the tires make one revolution. The higher the number, the quicker the acceleration.

Usually the higher number gear ratio will get slightly worse fuel mileage, as you will be turning more rpm at any given speed. Top speed on these trucks is limited by the computer, so the truck with the more agressive gears will get there faster.

I heard the 3.73 was only offered with the heavy payload 7700# towing package. Most people are real happy with the 3.55.

I would recommend getting the limited slip.

Without it, the 5.4 will easily spin the right rear tire. With the limited slip, when one tire starts to spin, power is transfered to the other tire. You can add an aftermarket limited slip later, but with labor to install it will be more expensive than if you get it from the factory.



[This message has been edited by dirt bike dave (edited 04-04-2000).]