I have(just bought) a 2003 Ex 4x4 XLT with a V10 and 4.30 axles. Thinking about changing to gears to 3.73. Is this a good idea?! Has anyone changed to or has a 3.73? What effect on driveability and fuel economy did it have? This truck is just for transporting the kids(no heavy hauling or towing).

 

If you're gonna swap the 4.30's out, then we can mett up and we can trade even - my 3.73s for your 4.30s.
Not sure why you are considering this change over unless you are stricylt using the X on long interstate runs. The 3.73's are OK for general driving and they are the most efficient on mpg's, but only by a few. The 4.30's are great for towing/hauling/climbing, but are generally 2-3 mpg's less than the 3.73's.
If you are truly serious about changing - depending on where you live (me in NC), I will travel to you and we can swap gears... I would love to have 4.30s

 

I have an X with the 4.30's, and I think the general consensus both here and on the V10 forum is we are lucky. The gas mileage difference is negligible, but it puts the V10 right in its powerband for cruising and hauling. My X got just over 14 mpg (14.1 actually, hand calculated) on a trip from Seattle to Modesto, California in July 2006. It is a 4x4 just for reference. I do try to keep it around 70 or less because after that the mileage dips significantly. Check out the V10 forum for some good info, also.

 

Thanks for the input. I was HOPING that the switch would make a HUGE difference in fuel mileage. But I guess i was dreaming! By the way i live in sw Oklahoma.

 

I have the 4.30s and if I keep it around 65 on the interstate, I can achieve 14.5 to 15.5 depending of road and wind conditions.

 

I've HAD the 3.73's behind my V10 and in 7000 miles towing (15,500#'s combined) I 'averaged' 7.8mpg including the Black hills, Big Horns and Rockies (so including some tough grades/climbs).

I do NOT drive my Ex much unloaded/not towing on the highway though as it is mainly a tow vehicle.

I swapped this spring to 4.30's...WHAT A DIFFERENCE in aliveness for the V10!

This year towing 5000 miles (17,000#'s combined so actually HEAVIER) with 4.30's including the Appalachians (again some good grades/climbs) I 'averaged' 8.2 mpg's...so actually BETTER mpg's with MORE weight behind the Ex!!!...I attribute that to the fact I could run in OD much much longer with very few down shifts...when I was climbing the 7% grades I was able to maintain 3rd gear vs 2nd gear last year with 3.73's!...so overall the 4.30's mate up SO MUCH BETTER behind the V10 (IMO and towing experiences).

Around town is where I also notice slightly BETTER mpgs with the 4.30's...I attribute this to the fact that with the 4.30's the trans shifts so much quicker and smoother than the 3.73's...I'm in 3rd gear now before 30mph where before it always felt like it was 'hanging' to shift if you will...now very crisp, quick and smooth I feel makes for overall lower rpms even around town and a slight 1mpg BETTER average.

So I am SOLD on the V10/4.30 combo after trying BOTH for towing...there is NO comparison (IMO).

To change to 3.73's in 'hopes' of much better mpg's I feel would be foolish as you would be hard pressed to recoup the $1500-2000 outlay for the 4x4 swap of gears...but again that is just my opinion.

Good luck and Happy New Years!

joe.

 

That's the only thing i was hoping for when we found our Big X. I soooo want 4.30 gearing. But begger's can't be chooser's. GOt a good deal and someday i'll get my 4.30's.

 

i will swap ya i live in central texas and need 4:30 how far are you from ok city i have a 01 4x4 w 150k psd

 

Give it up - I had first dibbs

 

snooze ya lose i guess hey c&s pm me with the details

 

Thanks X_HEMI_GUY, that is exactly the information i wanted to here. This is my first Ford in 15 years and my first big SUV. I drive dodge diesel trucks and will always run the 3.55 over the 4.10, but i didn't know how the lower ratio in the Ex would do. Thanks alot for your input. I think ya'll have convinced me to stay with the 4.30!

 

a cheaper way to numerically lower your drive ratio is to get larger tires, and if you keep the width at 265-285, you will get better mileage on the highway as well as make it look better. I still get as good of mileage as others and I have 35s with a lift.

 

Looks like we both loose...

 

dude thanks alot! hahaha!

 

I agree stay wih the 4.30's. Get bigger tires and a Tuner. you wont et better MPG but you will be able to smoke the tires and leave the want to be sports cars sitting at the green light as you blow them away. I do and love it. Also I tow over 15K#'s (big Boat) and it tows with plenty of power on the hills. (stopping is another issue) I get 12MPG at 75, about 15 mpg at 65 and 17 at 55mph i you ever want to go that slow.