Hello, I have a 2008 F150 Fx4 with a 5.4L in it. I'm running 35's on it with a 6" lift. it currently has a 3:73 Gear ratio. with a 9.75In rear end. I'm wondering if anyone knows whether this rear end will accept a 4:56 gear swap

 

sure looks like it... https://www.nitro-gear.com/Ford-9-75....75-456-ng.htm

 

​​​​​​I put 4.56's in my '13 f150 with the 9.75 rear end. Also installed an eaton true track.

but it wasn't a 4x4

 

I went with 4:56 Yukon gears in my 16 Screw with a 6 inch lift and 35 tires. It will make a big difference in your acceleration.

 

anybody tried 4.10's? Ive been running around with the stock 3.55"s since i lifted it and went to 35's. It doesnt do terrible as a daily, but id like to start camper shopping and I know I want to go lower. I just dont want to go too low.

 

I have a 2015 F150 SCREW 3.5EB 4x4 6.5' bed and am looking to run 35's. Currently, the truck has 3.31:1 gears and I think they will be pathetic with the lift. Thus, I am thinking 4.10:1. Thoughts?

 

I think it would do well with 4.10's. I have your same truck but a 2014, so probably 600-700 lbs heavier, and I am running 315/70R17 Raptor takeoffs with the stock 3.73's and it does well. I've never felt it was underpowered. 4.10's might improve upon it a bit but I personally don't feel the need to move up from the 3.73's. And thats even with towing a 5500 lb travel trailer around Utah. The Ecoboost just doesn't seem to notice it.

Honestly, I would even maybe see what the 3.31's feel like before you drop the coin on 4.10's. You might be ok with it if its just a daily driver.

My Lexus GX, on the other hand, is a 300hp/330 ft-lb 4.6L V8 and I went from the stock 265/65R18's(30.5") to 285/70R17's(32.8") and that was very noticeable even with 3.91 factory gears. It could absolutely use a regear.

 

1st, this is the first time I have logged on to this forum in 10 years because I am trying to hunt some info down, but I saw your post and can give you some first hand experience with exactly what you're talking about, and that's what it's all about, right?

I have a 16 screw with the 5.5 bed and 3.31 diffs. I have been running a 35x12.50 for over 100k miles. from an acceleration standpoint my best 0-60 (and what I always tell people) with a preloaded sct tune and the stock tires was 5.75 sec. with the 35s I struggled to get under the 7 second mark. having said that, as a daily driver it never gave me problems and always had enough power for me, I just wouldn't drag race anyone. transmission and drive train are all original and I have had no problems.

I will say the towing capacity struggles though. I would frequently go into limp mode with 240+ coolant temps while pulling a 22' center console, granted I probably shouldn't be trying to pull at 80 mph but we all have our flaws.

I recently had to fix an exhaust manifold leak so, as any red blooded american would do, I decided to go ahead and upgrade everything I had to touch to get there. I am running a lot of bolt ons and now have some custom tunes and a couple days ago I did a 5.38sec 0-60 still with the 3.31s. so you can get accel back, though the gearing might be a cheaper way.

My thoughts, and understanding, is that if you adjust your TCM tune for the bigger tires, the transmission pretty much re-gears the truck for you. it seems to me that the reason people used to always talk about regearing is because it was harder to change shift points and stuff in the transmissions 25 years ago, I don't think it is nearly as critical these days.

now remember, do as I say, not as I do, because I am actually thinking about re-gearing as well. but I don't have many regrets in my path to this point and I don't think you need to make gearing as high of a priority as a good tune.

 

thank you for the information! I will wait to try it out first.

like you, I am waiting on my manifolds or turbos to have an issue so that I can upgrade everything.

 

As an FYI, ford released a new manifold design that is constructed of stainless steel and now utilizes and extra stud and slightly altered stud pattern.



These or possibly the BD manifolds seem to be the best option at this point. I personally have warped a CRP manifold after only about a year of use.