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Discussion Starter · #1 ·
Asking here so the remarks will be for an excursion not a pickup.

My limited slip is going out and I have a seal leak. So I was going to have both axles fully serviced with new LS and locker in the rear.I told them I have 35s, weigh 8800 lbs, and tow a 6k lb boat and a car trailer. They said they would go with a 4:56 gear. I think that would be too much, more like a 4:30. What do y’all think?
 

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2006 F350 SuperCab, 4x4, AT, Cab & Chassis, 9' flatbed, dually, studded/egr deleted
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Discussion Starter · #3 ·
I might be off base here, but that seems awfully high for what you're using it for.. My friend says he has 3.83, I think, and does just fine for an F250 pulling a 30' trailer or any other number of things.

Regardless, here's a good read on ratios: Gear ratio: How it affects horsepower, torque, and rear axle in trucks – MotorBeast
I was thinking 4:56 is really low as well. But I do want the ratio to be close to stock with the 35s. I was thinking a 4:10 at the least but a 4:30 would add some pep in it step. I’ll check out that link too.
 

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I was thinking 4:56 is really low as well. But I do want the ratio to be close to stock with the 35s. I was thinking a 4:10 at the least but a 4:30 would add some pep in it step. I’ll check out that link too.
4.30 would put more torque to the wheels, but it'd also be reducing your top speed and giving you worse fuel mileage.

I have 4.10's on 30's, with my 5r110w transmission, and my daily commute I'm averaging 70 mph = 2250 rpm's = averaging 12-15 mpg

Here are 2 calculators that you could use to help you out:

My friend who has the F250, 6.0, 3.83's, on either 33's or 35's - has told me that he gets 18mpg and he pulls whatever he wants. I'm actually considering going 3.83's myself because I commute more than I pull. Both of us have FICM tuning and ECM tuning, so that helps with the pep in the step.
 

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Regardless of what you're considering on doing, I would advise using the calculators that I've posted so that you can see real world numbers.

I don't know if the Excursion has the same transmission as the trucks, but if so - here are the gear ratios for the 5r110w: Ford 5R110W TorqShift Transmission Specs & Ratios
 

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4:56 are for like 38in tires and above. the 4:10/11s were used in the 99-07 DRW trucks and around 65mph you rpms are 500+ higher than with oem. meaning fuel economy is in the dumps for no real reason. With just 35s you could run a simple say 25hp heavy tow tune and be leaps and bounds ahead in towing performance while not hurting anything. It would ACTUALLY HELP keep transmission temps and egts low while towing too and for like $299 the hydra is a much more affordable thing to try vs regearing and regretting. Very rarely do the 7.3l excurions, OBS or superduties need to regear.

I had a 200 excurison so its not quite a TRUE comparision but only an exhaust and intake no tuning with the 6.0l I could spin those 35in tires easily. The 7.3l has a much better tow feel compared to my 6.0ls. I would highly encourage you to try a simple tow tune with the php hydra chip. You have no real need to re-gear with your current excursion specs and towing numbers....
 

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Discussion Starter · #8 ·
4:56 are for like 38in tires and above. the 4:10/11s were used in the 99-07 DRW trucks and around 65mph you rpms are 500+ higher than with oem. meaning fuel economy is in the dumps for no real reason. With just 35s you could run a simple say 25hp heavy tow tune and be leaps and bounds ahead in towing performance while not hurting anything. It would ACTUALLY HELP keep transmission temps and egts low while towing too and for like $299 the hydra is a much more affordable thing to try vs regearing and regretting. Very rarely do the 7.3l excurions, OBS or superduties need to regear.

I had a 200 excurison so its not quite a TRUE comparision but only an exhaust and intake no tuning with the 6.0l I could spin those 35in tires easily. The 7.3l has a much better tow feel compared to my 6.0ls. I would highly encourage you to try a simple tow tune with the php hydra chip. You have no real need to re-gear with your current excursion specs and towing numbers....
Regardless of what you're considering on doing, I would advise using the calculators that I've posted so that you can see real world numbers.

I don't know if the Excursion has the same transmission as the trucks, but if so - here are the gear ratios for the 5r110w: Ford 5R110W TorqShift Transmission Specs & Ratios
I’ve got the super panty dropper tune with garret 1 turbo, and Hercules fuel tune and I’m no where close to chirping tires let along spinning them.
 
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Discussion Starter · #9 ·
i re-geared to 4.30s with stock 20's (34" tire) and love it for towing here in the western us, even in town the get up and go is much better than with the 3.73s. fuel mileage...i dont drive a ridgeline
I’m probably going 430. Stock is 3:73 and I don’t see paying to go to a 3:83 if that’s a real size or even a 4:10 if available for 4x4. I think 4:30 will be my best bet, I just wanted to hear someone else say what they went with. Thanks
 

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How many miles on the truck? anything around 250k and above your injectors and HPOP are really tired. Not that its a reason to replace them. But in 2018 I replaced my 1999 7.3l HPOP after some misdiagnosing and intermitant IPR failure. It was a nice bump in power to say the least lol.... Plus running a run and a stage one turbo. You've got all the air you need but if the injectors/hpop are not putting out it will hamper the tune/injector combo esp towing etc.
 

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Yea...I can't find any evidence of 3.83, so I may have just misheard my friend. There is a 3.73.

Regardless - I just provide the calculators and what little I know about the issue. Good luck with whatever choice you pick.
 
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Discussion Starter · #12 ·
How many miles on the truck? anything around 250k and above your injectors and HPOP are really tired. Not that its a reason to replace them. But in 2018 I replaced my 1999 7.3l HPOP after some misdiagnosing and intermitant IPR failure. It was a nice bump in power to say the least lol.... Plus running a run and a stage one turbo. You've got all the air you need but if the injectors/hpop are not putting out it will hamper the tune/injector combo esp towing etc.
had the hpop and injectors replaced about 100k ago. As far as I know I’ve never had the ipr replaced unless they did it when getting studded.
 

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had the hpop and injectors replaced about 100k ago. As far as I know I’ve never had the ipr replaced unless they did it when getting studded.

So you got a 7.3l studded or you got a 6.0l studded? Just want to make sure because this is the 7.3l section but studding a 7.3l is just really not common for a turbo and tunes etc.
 

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Discussion Starter · #14 ·
So you got a 7.3l studded or you got a 6.0l studded? Just want to make sure because this is the 7.3l section but studding a 7.3l is just really not common for a turbo and tunes etc.
6.0. I just noticed I picked the wrong section. Sorry bout that
 
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Yea...I forgot where I was as well..
 

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6.0. I just noticed I picked the wrong section. Sorry bout that

You may want to get your tuning adjsusted. You should have absolutley NO ISSUES with your current set up. The 6.0L STOCK tuning is way ahead of a stock 7.3ls etc. Plus the 5R100 has a true tow mode where as all the 7.3l did was turn off overdrive. The 5R100 behind the 6.0l is a very nice unit to tow with and the oem programming for the stock tow mode is very good.
 

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I’m probably going 430. Stock is 3:73 and I don’t see paying to go to a 3:83 if that’s a real size or even a 4:10 if available for 4x4. I think 4:30 will be my best bet, I just wanted to hear someone else say what they went with. Thanks
its slightly over-geared from what a truck with 4.10s would have, but for my purposes that is fine. your 35s will drop down the highway rpms just a bit more and make them just about perfect. 4.56s would be way too much, would be better matched with 37 or bigger tires.
 
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