New here, I also have an 01 supercrew Lariate, I have been thinking bout 410 gears, but I can't figure out what size of rear end I have and what is the stock gear. I have been told they are the same as the f250's ? also do you need to change both rear and front, if so what are the advantages. I drag a 2up sled trailer throught Wa passes, and snow filled logging roads. Please advise. [IMG]http://[/IMG]

 

Welcome ! There is an axle code on the driver's door jamb sticker. The codes can be searched here. There is a tag under one of the rear end cover bolts. The second line of information begins with the ratio, possibly an L for LS, and the size. You get a 9.75" out back with the 5.4 and a 8.8 with other engines. All 4X4s have a 8.8" up front that requires reverse cut gears. Gear changes in 4X4s require the front and rear gears to be changed. The F-250s have a 10.25" in the rear. Going to 4.10s from any available ratio you may have will yield greater acceleration, towing ability, and performance. You will still have plenty of top-end speed, but highway mileage will decrease based on the difference in ratios.

 

Thanks, Max Mitchell. I did locate the rear tag 9.75 with 8.8 in front is correct. would 410's go in each or what, since the front is used in 4wh position only? You also mentioned hwy milage will decrease! is this because of speed or consistant travel

 

You're Welcome ! Typical 4X4 installation is front and rear gears. You're highway mileage decreases because if you compare both ratios going a similar speed, you're turning higher rpms with the 4.10s.