Just curious a bit. I've got a 05 f250, v10 . Going to swap gears and would like to know what you guys have installed. I'm running 35s. Should I go with 4.30s or 4.56s ? Any input would help out

 

4.30 was a stock option for the V10, since you tow and have 35's the most common swap to get back to stock is 4.88 gears. But if you don't tow real heavy and want a stock tire/3.73 combo a 4.56 gear swap will do that. I have a 5.4 and swapped in 4.30 gears, now it made a huge difference but I only run a 33" tire if I went to 35's I would have picked 4.88 gears. Actually a 4.56 gear with my 33's would be perfect in my opinion the 4.56 are only 200rpm more than my 4.30 at 65mph and since I don't drive over 68 or 70mph max on the highway it wouldn't bother me

Sent from my iPhone using IB AutoGroup

 

Hey thanks for the info! Since I posted, I found my axle code. It says 4N. I found a axle code site and it says I've got 4.10 lim slip. Right now at 60 I'm turning bout 1750ish , and I'd like to be in that 2000 range at 60. With 4.56s, would that be pretty good? I don't pull 5th wheel trailers as I sit too high, so mainly bumper pull car trailers.

 

I have an '05 Excursion with the 2 valve V-10, your 3 valve motor makes a little more HP/TQ. We pull fairly heavy TTs, 9.5 to 10.5k lbs and the factory 3.73 gears didn't make for happy trails, it got us there but with a lot of shifting and what seemed like lots of effort. I also upgraded my suspension to modded F-350 springs all around, resulting in a 4" lift and much improved road manners. With my new ride height I decided to go with 35" tires so after crunching the numbers I selected 4.88 gears. With my 35.24" Nitto Duras and the 4.88s the truck now has an effective ratio of 4.39. This has proven to be an excellent combo for towing heavy, the EX stays in OD much, much more now and that has boosted the towing MPG by 1.5 MPG. The motor seems to like running at the slightly higher revs where it makes more power, I haven't found any downside to this gear/tire swap.