Can someone school me on re-gearing the excursion and what the difference is between boxes? I’m assuming you go from high torque to high speed, or am I way off?

If I’m building a rig that is for overlanding, long trips no towing. Currently it’s stock. Should I just stick with that or is there a gearing that would treat me better? Thanks for the info.

 

Boxes??? Are you talking about re-gearing the differentials or the transfer case?
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No towing, leave it alone unless someone put taller tires on it.

@Antonm are you trolling on the transfer case? I can't wait for the response!

@WE3ZS Tom, enjoy chiming in...you V10 Tow Dawg.

 

Not trolling at all, he said, and I quote "what the difference is between boxes?"

The only "box" I could think of is the transfer case.
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I suspect he is referencing the differentials. How the rig will be used as "overlanding" could mean many things, "long trips" means what exactly? Are plans to change tire size, increase height or width? What is present ratio now?

 

The Ex IS a big box!

 

More info will be needed to offer any advice on which gear ratio might be your best setup.
Yes, deeper (higher numerical number) ratios will apply the available torque to the ground more efficiently while lower numerical gears will allow for a given cruising speed at lower RPMs, which in most cases means improved MPGs.
Several factors need to be considered to decide which gear may be the best choice for a given vehicle.
No towing is good info. Deeper gears typically provide better towing performance.
What size tires will you be running? A taller tire than stock acts like a lower numerical ratio as it causes the vehicle to travel farther (than stock) on each full rotation, just like a lower numerical ratio.
Will the vehicle be used on rough low speed offroad terrain frequently or mostly paved roads at higher speeds? Overlanding can mean lots of different things to different folks.
How heavy will the finished ready to travel vehicle be?
Will the best possible MPG or best possible performance be a higher priority goal?
Will there be an other performance mods done to the drivetrain?

I'm sure there will be more questions to follow up, but answering those above will help to fill in the blanks we currently have.

 

Personal preference from the 3.73 get up and try to go to a higher gear that will help get the heavy rig up a small hill.

4:10 or 4:30 is what I would go with if I wasn’t towing. Probably 4:30. I have a 4:56 for towing, which I like, but for everyday, it’s a bit much.

Just my opinion.

 

Gearing is directly related to your tire size. The V10 Super Duties (and EX's?) came with either a 3.73 or 4.30 gear set. Check your differential and/or door jam sticker.

What size tires are you planning on running? Are you planning on doing a lot of low speed offroading and/or deep sand? How much weight are you planning on? It depends on your usage.

For what its worth, I run 35" tires, do 1-2 trips down to Cabo every year, as well as the Sierras and the deserts several times a year. I have about a 1500lbs constant load. My stock gearing of 3.73 was not cutting it in deep sand, steep climbs and long mountain passes. Low power, low torque and the transmission constantly searching for a gear, etc. Most people on this forum would recommend a 4.30 effective gear ratio. With the 35's I went with a 4.88 gear set which gives close to a 4.30. With my driving however, I may have been happier with even a deeper set, but that would then start affecting high speed fuel efficiency.

 

I’m curious to how much going from 3.73 to 4.88 would cost on a v10 4x4 Excursion. If one would do the work himself? What about having a shop do it? It’s always fun to fantasize about a gear swap, but often the cost involved is overlooked. I’m guessing probably $3k for DIY and $4500 for a shop????

 

DIY, probably in the $1000-1500 range depending on what name brand of parts your buy (assuming you already have the required tools).

Shop price will include labor rate & shop fees that come out to give or take 150/ hour and expect 16 hrs of labor (so $2400-ish in labor), so total shop should be around $4,000 or so ($2400 labor plus $1500 in parts). And that assuming they don't find anything else wrong while they're in there (u-joints, wheel bearings, etc.)
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So $1500 DIY for both the front and rear diff? That isn’t so bad.

The shop will definitely find more stuff. 20 year old 3/4 tons!!!! Hell, I find more stuff every time I crawl under it.

 

Yeah, gear sets are give or take $400 a set (see link below)

https://www.randysworldwide.com/shop/yg-f10-5-488-31


Master install kit is $500 (looks like they've gone UP recently).

https://www.randysworldwide.com/shop/yk-f10-5-a

I'm sure you can get stuff cheaper than Randy's , although Yukon parts from Randy's is a top shelf stuff from a reputable vendor for sure.
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Awesome info!! Thanks for your time.

 

Here is my contribution. Useful link below.

https://www.drivetrainshop.com/Articles.asp?ID=263