Hey, i have a 06 F150 FX4 with a 6 inch lift on 35's and i want to regear to either 4.10 or 4.56. I have no clue on what type of gears i need to get. What brand is the best and which ratio would be best. I do moderate offroading and mainly drive in the city. I want the limited slip in the rear but i dont know what i need in the front. Thanks for your help.

 

Sounds like you've got a nice truck. I'd opt for 4.88's with your configeration. The 4.56's would get you back to "stock" operation, but with the added weigh the 4.88's would be your best choice IMO. The Detroit Tru-Trac is a very good limited slip for the front and rear, I just put these in my axles and love them. Richmond and Motive gear make good gear sets at a pretty reasonable price. I went with Motive Gear because they are an OEM gear and are very quiet. Look to spend about $2000 for the whole thing, that's gears, limited slips and installation. Hope this helps.

 

If i already have the stock limited slip in the rear can i just buy new gears, or will they not fit in the stock differential? Also, for the front, would i need to buy a new defferential to change the gears even if i didnt want the front to be limited slip? Thanks.

 

You can just buy the gears, you don't have to buy a new limited slip. The same goes for the front, just buy the gears. The only reason I put the limited slips in was because I didn't have a factory limited slip and it didn't cost any more for installation.

 

Ford does not put Limited slip in the front diff. Just rear. All fronts are open.

 

Oh Ok. I think ill go with the Motive Gear 4.56. I guess i will leave the stock limited slip in the rear and i may put detroit tru-tracs in the front. Motive Gears website says the 4.56 gears are 9.75 inches with 31 spline, what does this mean? Is this the only size that will fit the ford axle, and do the number of spline make a difference because ive seen other gears with more or less spline? Im new at this so i dont really know anything about different gears. Thanks for your help.

 

Drew, tell us a little more about your truck i.e. motor size, auto vs. manual and stuff like that. If you also give us the axle codes from the axle or the door then we can help you find out what your axle is. If it's a 5.4 litre then you have a 9.75 rear axle and if it's a 4.6 then you have a 8.8 rear axle, either way you have a 8.8 ifs up front. (Anyone can correct me if I'm wrong) The spline does make a difference, for instance, the 8.8 in the mustang has less splines than the 8.8 in the F-150, so you do have to be carefull. Hope this helps.

 

Its an 06 5.4 liter 4x4 supercrew automatic, i think its an FX4 but im not positive because it doesn't have the FX4 sticker on it. When i did a history report it said it was an FX4 so i assume it has the limited slip in the rear, but I cant read the number on the axle. Thanks for your help.

 

x2
Added weight plus added rolling resistance and aerodynamic drag.
You want the shortest rear-end you can get so your acceleration remains good.

I run 4.10s with street tires (approx. 31 inches), with 35's you want all the bite you can get.

 

I'm pretty sure you have the 9.75 axle, so the motive gear 4.56's that your talking about will work fine. You'll have to let us know how you like it when it's all done. Glad to be of some help for you.