Hi,
I have a 2000 F350, V10, crew cab, 4x4, 78k miles. Bone stock including wheels and tires. And I have air bags.
I just bought a 24' deck over gooseneck and will be hauling a couple of my off road buggies. I don't know the exact weight of the combination. I will look into that, but I think it should be around 10 to 11k.
I towed the empty trailer home about 600 miles, through the Rockies in CO. It wasn't exactly fun on the passes, as you can imagine. I tried to keep the RPMs around 3500 on the hills, it was slow, but I don't mind that. It went great on the flats.
I'm not going to buy a diesel, so I'm thinking about a regear for my truck and wondering what benefits I can gain from 3.73 to 4.10 swap. I realize I will loose some MPGs. This is not an issue. The truck is used only for it's intended purpose of hauling and towing.

Thanks

 

3.73's to 4.10s isn't a big jump, so you won't really notice much change in RPMs, mileage, or pulling power. You'd need to jump to something serious, like 4.58 or higher, to really see any changes.

IIRC the V10, much like the 5.4, needs to rev to make power (though not as high as the 5.4) because it's an overhead cam engine. Those are notorious for needing to spin up to make their power. It's got a lot more torque than the 5.4 though, so it gets off the line better. But your max horsepower doesn't come in until 4250 or 4750 RPM depending on the year of the engine (yours is a 2000 so you're at 4250 RPM). Heck even your max torque, being a 2000, doesn't come in until 3250 RPM, so you were JUST past your max torque. Get those rev's up and you'll be happier with the pulling power, even if it sounds like it's going to come apart.

Most modern gassers aren't like the old big blocks of years past - they need RPMs to make power, where the old big blocks made their power in the lower end and couldn't rev high or they'd come apart. Newer engines don't have that problem.

 

So with the stock tire size, is 4.56 the way to go? I feel that'll really put a hit on the MPG. But that's ok, within reason.

Thanks.

 

The V10 was available from the factory with 4.30 gears, but not 4.56.

 

Glad I asked. Now I'm leaning heavy to the 4.56.
Any other thoughts on the 4.56? For example RPMs at 65 MPH with an auto transmission, with OD on and off.
I was initially thinking 4.10s because I already have a used set, but that will not be the deciding factor.
how do I correct the speedo?

 

We drove 2 Uhauls with V10's across country a few years back. Curious what they were geared at as they spun pretty high. I wanna say either truck was getting a consistent 9mpg and were fully loaded with furniture etc. I'll add you had to push the O/D Button to make it go into OD otherwise it stayed out. Basically reverse of what the pick ups are. There was stickers on the dash which warned not to use OD if the trucks were loaded.

 

Correcting the speedo can be done in Forscan. If you have 4.10's I'd go that route first, mileage will be good and you'll gain some power on stock diameter tires. Once you do a gear change on the 10.5 once you be able to do it again if you wanted 4.56's in under 2 hours, wicked easy.

 

Well, I thought I had a complete set of 4.10's. Looks like now I have 4.10's for the rear 10.25 only.
I'm starting the regear in one of my crawlers. It has the D50. Or so I thought, based on the pronounced hump on the top. But it looks like it has D60 carrier and shafts............
I'll start another thread on that.

 

My V-10 Excursion had the factory 3.73 gears and was getting 7 to 7.5 MPG towing our old 31’ 9,500 lbs toyhauler on trips up and down the Eastern seaboard. I swapped in a set of 4.88 gears and on the next trip from Philly to SC and back it got a solid 9 MPG. The mileage increase was due to it being more into the “power band” of the 6.8 which in turn resulted in far less downshifts. With the 3.73s it would drop a gear just running up and over an Interstate overpass, with the 4.88s it didn’t downshift a single time (on the Interstate) the entire trip, big difference! I always do all of my towing in OD and let the trans do its thing, I also use the 5Star Tuning 89 octane performance tune when towing. The unloaded mileage dropped from 14-ish down to 12-ish but the big wagon was primarily our tow rig.
All of this was on 32” tires vs the factory 31.6”, so not much of a difference. At 65 MPH with the 4.88s it spun at 2430 RPMs, far from screaming. After the upgrade to 35” tires which gives an effective 4.39 ratio the RPMs dropped to 2230 at the same 65 MPH.
In my opinion based on my V-10 towing experience the 3.73s are just barely adequate, the 4.30s are a great all around upgrade for towing and running solo, the 4.56 is a sweet set for a dedicated to rig and 4.88s are the shizzle if only towing heavy all of the time.

 

Here’s a good site for playing with your ratios, tires sizes, drives etc and seeing where you will end up. Drop down menus for most trans / transfer cases etc.

Gear Ratio Calculator

 

 

If you have any inclination of going to a slightly larger tire down the road, I'd go with the 4.56's. A couple years ago, I put on 285/75-16 Coopers and went with 4.56's (from 3.73's) in my '03 F250 4x4 V10. Effective ratio for my combo is 4.40. It's one of the best mods I've ever done. As said above, it definitely holds a gear longer while towing and much more effortless getting up to speed. The gears have made towing our 6K lbs boat in and around the Northern California mountains a game changer and looking forward to towing heavier.

Haven't really noticed a change in around town mpg, but I also get into the throttle a time or two (every drive) as it can be a little addicting.
Highway, I like to keep between 65-70mph:

65mph - 2250 RPM
70mph - 2450 RPM

Recently towed my daughter's Jeep from Northern California to Salt Lake City. A lot of elevation changes and a lot of towing @ 5000 ft and above with cross/head winds. Was at 65mph (cruise control engaged) the whole way out and netted 10.5mpg. What I really liked is how easy (and authoritatively) the transmission down shifted to 3rd (in cruise control) while traversing a grade. Sure, if I had a heavier pull, I'd be more involved (manually with the OD), but it was a nice experience that I attribute mostly to the gearing.

On the return trip(unloaded), I bumped it up to 2,500 RPM (72mph) the whole way and netted 13.5mpg. It was nice and smooth at that rpm. These engines(and transmissions) like to run free.

 

I'll go with 4.56.
Thanks all.

Starting another thread for the axle.

 

This is what I based my gear purchase on and it is not 100% reliable.

 

My '11 6.2 is at factory 4.30 and I'd love a little more in CO. Going to 4.56 is not worth it so if I did anything it'd be 4.88.

I'm not the least bit worried about mileage in a CCLB 4X4