3.73 vs 4.11 in a 2008 E350 V10

[Steve Hunt]

Anyone have first hand experience with 3.73 vs 4.10 rear diff ratio in a E350 V10. I will need to tow 5000 ish lb trailer weight 40% of the time and trying to decide if I need to switch from 3.73 to 4.10. The van is getting a 4X4 conversion and will run 275/70-18 tires (I think that converts to a 32-33" diameter). I've only driven the van in stock configuration 2wd 3.73 and was a little underwhelmed with the V10. I've been told the V10 3.73 setup is a good combo but adding weight to the van build, little taller tires, 5000 lb trailer...it adds up.

Thanks

 

[boywonder]

I have a 4WD 5.4L V8 with 3.73's and 285/70-17's...

I'm fine with my setup but it downshifts out of OD on moderate (or steeper) grades.....can't imagine pulling a 5000 lb trailer with my setup ....but hey...FL is flat.

I also like the gas mileage of the 3.73's, but out here in the mountains there are many times when 4.10's would be better.


Try the search feature..this subject has been discussed here numerous times.

 

[mikracer]

I have the same engine and trans as your van and I run 4.10's on 285's. I have a small toy hauler that weighs about 7,000lbs and although the van does fine pulling it, I sometimes wish I had lower gears.

 

[JWA-SMB]

Certainly changing rear gears could be an answer but if I had a V10 gasser I'd look into a new ECM tune such as 5Star Tunes. This link will take you to their page for E-Series w/V10 engines.: https://5startuning.com/product-category/1998-2014-e-series-6-8l/

This outfit has received rave reviews from actual users who post to FTE. In fact there's an entire multi-page thread complimenting them along with a few less-than-glowing reports too. FTE has created a separate folder for 5 Star topics, can be found here: https://5startuning.com/product-category/1998-2014-e-series-6-8l/

A few caveats...........

-I'm NOT a user as I only drive 2WD E-Series with 5.4 gassers.

-I never tow anything and rarely venture more than 200 miles outside of Columbus Ohio. Any elevation changes I'd see would be 1,000' or less.

5 Star Tunes can be configured to change a lot of PCM-controlled parameters like transmission shift points--basically anything it controls can be tailored to suit your needs. Their tunes can be very easily reversed so its not a permanent change by any means.

Changing rear gears might be the better option especially if heavily loaded or towing frequently--5 Star Tunes just something to consider.

 

[carringb]

I would definitely change gears if you are going to taller tires. 4.10 however, might only give you the same effective ratio as what you have now, running taller tires.

4.30 gears are the sweat spot for the V10 with 4x4 IMO. With 32" tires, you end up with an effective ratio of 4.10, but you can run up to a 35" tires and still fall within a 3.73 effective ratio. Effective ratios taller than 3.73 aren't really recommended for towing.

Also, don't forget to consider combined weight ratings since you're towing:
3.55 - not rated
3.73 - 15,000 pounds
4.10 - 18,500 pounds
4.30 - 20,000 pounds
4.56 (with 10.75" or larger ring gear) - 22,000 pounds

 

[Steve Hunt]

Great input from all of you, thank you, just the kind of real world experience I need to consider.

Having lived all my 59 years in Florida the last thing i want to do is cruise around here, so there is "that"

Steve

 

[Twoxentrix]

Along with the combined weight chart carringb provided previously, I found it beneficial to also get an idea of how the different variables impact the outcome utilizing the one of these performance calculators:

https://www.crawlpedia.com/calculators.htm

Tire Size, RPM, Speed, and Differential Ratio Calculator

https://www.crawlpedia.com/rpm_gear_calculator.htm

If you havent already, Consider pulling up spec on your engine (specifically the torque curve)

Gas engines peek torque at higher rpm's than Diesel engines, so knowing at what level rpms deliver the best torque helps you manage selecting the right gear to be in (you'll have to ballpark effects like weight and road grade)

I also used the calculators to get an understanding of what rpms will net me the best cruising speed & fuel mileage - and ruffly what mph that sweet spot is.

 

[Steve Hunt]

Along with the combined weight chart carringb provided previously, I found it beneficial to also get an idea of how the different variables impact the outcome utilizing the one of these performance calculators:

https://www.crawlpedia.com/calculators.htm

Tire Size, RPM, Speed, and Differential Ratio Calculator

https://www.crawlpedia.com/rpm_gear_calculator.htm

If you havent already, Consider pulling up spec on your engine (specifically the torque curve)

Gas engines peek torque at higher rpm's than Diesel engines, so knowing at what level rpms deliver the best torque helps you manage selecting the right gear to be in (you'll have to ballpark effects like weight and road grade)

I also used the calculators to get an understanding of what rpms will net me the best cruising speed & fuel mileage - and ruffly what mph's that sweet spot is.

Very nice!! Look forward to checking this out in the morning.

 

[deserteagle56]

I went straight from 3.73 to 4.56 gears with my E350. Best mod I've ever done. No more shifting down on every little grade and more importantly since I drive a lot of dirt roads at 45- 50 mph, the tranny stays in OD now at those speeds. With the 3.73 gears it was constantly shifting in and out of OD at those speeds which can't be good for the tranny. That V-10 thrives on rpms so changing the gearing made it much happier. And for whatever reason, the fuel mileage stayed the same after the gearing change.

 

[Steve Hunt]

I went straight from 3.73 to 4.56 gears with my E350. Best mod I've ever done. No more shifting down on every little grade and more importantly since I drive a lot of dirt roads at 45- 50 mph, the tranny stays in OD now at those speeds. With the 3.73 gears it was constantly shifting in and out of OD at those speeds which can't be good for the tranny. That V-10 thrives on rpms so changing the gearing made it much happier. And for whatever reason, the fuel mileage stayed the same after the gearing change.

I hate a hunting trans for sure.

What is your gas mileage, van only?

So Quigley set it up as 4x4 with 3.73 and then you later changed it to 4.56. How much $ per end to make a gear change like that? In my case, theoretically we buy the front axle already the ratio i want and then change the rear.

 

[carringb]

I have 4.56 gears as well, since I tow heavy. I average 12 MPG highway, but mine's a dually so that's already a penalty. And I tend to drive it pretty hard. The low gears are definitely a disadvantage when solo, but I gained 1.5 MPG towing, because with the low gears, I stay in overdrive all the time, except when climbing passes.

One advantage to 4.30 gears, is you can find front Superduty axles with that ratio. Not the case with 4.56 since that's an E-series only ratio.

 

[deserteagle56]

I hate a hunting trans for sure.

What is your gas mileage, van only?

So Quigley set it up as 4x4 with 3.73 and then you later changed it to 4.56. How much $ per end to make a gear change like that? In my case, theoretically we buy the front axle already the ratio i want and then change the rear.

Overall mileage since I bought the van 12 years ago is 11.8 mpg. That's calculated by an Excel spreadsheet I have set up, not a guess or a figure taken from a dash readout that's rarely accurate.

It came from Ford with 3.73 gears. Quigley merely added a Superduty front axle geared the same - and since Ford E-350 vans come stock with 8 x 6.5" bolt pattern wheels and the Superduties come with 8 x 170mm, Quigley added adapters to the rear axle to make it 8 x 170mm also. I've had no problems with that setup. I don't remember (12 years ago!) the exact cost but it was expensive because at the same time I had it regeared, I had the guy (local) put in ARB air lockers front and rear. If memory serves me correctly the ARBs were ~ $1000 an axle alone, not counting the gears and labor to install. Looking back after all these years, this was money well spent. Love this rig.

 

[Steve Hunt]

Overall mileage since I bought the van 12 years ago is 11.8 mpg. That's calculated by an Excel spreadsheet I have set up, not a guess or a figure taken from a dash readout that's rarely accurate.

It came from Ford with 3.73 gears. Quigley merely added a Superduty front axle geared the same - and since Ford E-350 vans come stock with 8 x 6.5" bolt pattern wheels and the Superduties come with 8 x 170mm, Quigley added adapters to the rear axle to make it 8 x 170mm also. I've had no problems with that setup. I don't remember (12 years ago!) the exact cost but it was expensive because at the same time I had it regeared, I had the guy (local) put in ARB air lockers front and rear. If memory serves me correctly the ARBs were ~ $1000 an axle alone, not counting the gears and labor to install. Looking back after all these years, this was money well spent. Love this rig.

I have 4.56 gears as well, since I tow heavy. I average 12 MPG highway, but mine's a dually so that's already a penalty. And I tend to drive it pretty hard. The low gears are definitely a disadvantage when solo, but I gained 1.5 MPG towing, because with the low gears, I stay in overdrive all the time, except when climbing passes.

One advantage to 4.30 gears, is you can find front Superduty axles with that ratio. Not the case with 4.56 since that's an E-series only ratio.

Great Tribal Knowledge, big help! I think everyones info helps lead me to the conclusion of whats going to work for me all things considered. I'm going to get a Superduty front axle with the 4.30 and then change the 3.73 stock rear to match and at least do a locker in the rear while they're in there.
I can live with 12 mpg, use to that anyway. Bad drive-ability would wear me out before 12 mpg would anyway.

 

[E350-SMB]

Also, don't forget to consider combined weight ratings since you're towing:
3.55 - not rated
3.73 - 15,000 pounds
4.10 - 18,500 pounds
4.30 - 20,000 pounds
4.56 (with 10.75" or larger ring gear) - 22,000 pounds

carringb: If you don't mind, what "rating" do you mean by "3.55 not rated." My 2002 7.3 van came from the factory with 3.55. Are you saying that it was not rated for towing any weight whatsoever? Where would any rating info be? On the driver door pillar sticker or on the window paper sticker? On the driver's door pillar it says "GVWR 9400LB." What should I look for?

 

[carringb]

carringb: If you don't mind, what "rating" do you mean by "3.55 not rated." My 2002 7.3 van came from the factory with 3.55. Are you saying that it was not rated for towing any weight whatsoever? Where would any rating info be? On the driver door pillar sticker or on the window paper sticker? On the driver's door pillar it says "GVWR 9400LB." What should I look for?

I'm referring to Ford assigning a GCWR to the V10 specifically. It just was never offered as an option, probably because peak torque happens higher than the 5.4L, so it might have ended up with the same or even lower GCWR than the 5.4L with that tall of an axle ratio.

The GCWR for the diesels with 3.55 gears is 16,000 pounds.
GCWR for the 5.4L with 3.55 gears is 12,000 pounds.

The GCWR tables are listed in your owner's manual.

 

[carringb]

I'm going to get a Superduty front axle with the 4.30 and then change the 3.73 stock rear to match and at least do a locker in the rear while they're in there.
I can live with 12 mpg, use to that anyway. Bad drive-ability would wear me out before 12 mpg would anyway.

Before you pull the trigger on that, you might want to price-shop a used SuperDuty rear axle. One with a factory e-locker is probably cheaper (maybe much more so) than replacing your existing gears and adding a locker to that. I'm assuming you have an '05+ Quigley conversion? If so, you have adapters on the rear axle, and swapping axles will match you your bolt pattern and track width without adapters. And if you have a semi-float rear, these axles are on the weak-side, and have a pretty terrifying failure mode.

 

[Steve Hunt]

Before you pull the trigger on that, you might want to price-shop a used SuperDuty rear axle. One with a factory e-locker is probably cheaper (maybe much more so) than replacing your existing gears and adding a locker to that. I'm assuming you have an '05+ Quigley conversion? If so, you have adapters on the rear axle, and swapping axles will match you your bolt pattern and track width without adapters. And if you have a semi-float rear, these axles are on the weak-side, and have a pretty terrifying failure mode.

Timberline Vans has the van (2008 V10 extended) now to do the 4x4 conversion among other things. They are going to look at pricing and availability on what you described. Thanks

 

[tcdave]

I have 2002 e350 with V10. Have 4.10 with 285 tires. Towing my 4500lbs trailer works fine. Towing my 7700lb trailer wish I had 4.30 gears.

 

[sierraoneill]

I've got 4:10's in mine with a 5-star tube. Mine is 4x4 high top, and I get 10 to 12 mpg on the freeway cruise control locked in at 70mph. I changed gearing when it was still a 2wd drive van and no lift, but I preferred the 4:10's even as a low top and unlifted rig.. . back then I averaged 12 to 15 MPG cruising 70 to 75 MPH.

Towing wise, I don't really tow too much, but I noticed a big difference in the switch on the low end.

FWIW!

 

[Jorje Pablo]

Anyone have first hand experience with 3.73 vs 4.10 rear diff ratio in a E350 V10. I will need to tow 5000 ish lb trailer weight 40% of the time and trying to decide if I need to switch from 3.73 to 4.10. The van is getting a 4X4 conversion and will run 275/70-18 tires (I think that converts to a 32-33" diameter). I've only driven the van in stock configuration 2wd 3.73 and was a little underwhelmed with the V10. I've been told the V10 3.73 setup is a good combo but adding weight to the van build, little taller tires, 5000 lb trailer...it adds up.

Thanks

IMHO you're fine with 3.73s if you just uncork the V10 and let it breathe, the stock exhaust is VERY restrictive and requires a few modifications starting with the Y-pipe which resembles more of a T then a Y. I redesigned mine using SLP 200cpi catalytic converters, eliminated the T and used a Merge Collector from Vibrant Performance, then i used a Flowmaster 50 Series SUV Muffler, next up was an SCT X4 programmer and 87 octane tune from 5 star.
The butt dyno feels like i swapped out the V10 for a V12 and it runs like a scalded dog.
You can swap out your gears and spend the same amount of money (probably more) and you won't be nearly as satisfied with the end result, you'll still have a dog for an engine and you might have some gear whine if they aren't installed correctly.
Other mods include a 170 degree thermostat, Wix 46418 air filter and D.U.I. SOS coils ($370), keep in mind my V10 is a 2008 model and it's also a Jasper reman.
The engine runs cooler, makes a LOT more power and if i keep my foot out of it, gets better mileage. My goal when building the engine was not to make more power, my goal was to reduce operating temps, increase BMEP, fuel mileage, volumetric efficiency and engine longevity, the side effect was more power.
There's always more then one way to skin a cat, this was my choice, do it like you want too..
This forum doesn't allow me to add pics in normal fashion but if you want pics send me a PM and i will give you my email.. :b5: