3.73 vs 4.10 gears - fuel economy?

[wildbill23c]

I have a 3.73

I have a 3.73 rear end , open differential. I'd like to have an e-locker and 4.10 gears in it someday.

I'm thinking of doing a limited slip in my Bronco 2 as well, but think a gear swap to 4.10's would be a good idea too with the larger tires, help a bit with the power loss with the larger heavier tires I think. I'm looking at maybe the Lock Rite for the rear, should be good enough for a daily driver. I was quoted almost $1600 to have an Eaton Tru-Trac put in, that's way too much money IMO. I've heard several people with the Lock-Rites and have no issues with them, so I may try that route for $400, and that's something I could install myself if I don't change gear ratios...which if I do change the gear ratios I think I'd just have the shop to that part and I'd install the Lock-Rite myself as there isn't much to doing that as you are only pulling the spider gears out of the carrier and replacing them with the Lock-Rite assembly (Lunchbox Locker). For what I use my Bronco 2 for it would do just fine, its mostly a daily driver with a few backroads drives and fire trails and forest service roads. Just be nice to have that added traction in the snow and the occasional mud up in the hills.

 

[8thTon]

As for mileage, it really will depend on the terrain you're driving on. Cruising on the highway you'l likely lose a bit, but that might be made up at lower speeds if you're driving hills. If you could add another overdrive gear you'd be set, but you're stuck with 5.

I know I would not trade the 4.10's in 3.0, and I'm getting around 17 on winter blend fuel right now - sometimes a bit more, sometimes less, and I don't baby it.

 

[wildbill23c]

As for mileage, it really will depend on the terrain you're driving on. Cruising on the highway you'l likely lose a bit, but that might be made up at lower speeds if you're driving hills. If you could add another overdrive gear you'd be set, but you're stuck with 5.

I know I would not trade the 4.10's in 3.0, and I'm getting around 17 on winter blend fuel right now - sometimes a bit more, sometimes less, and I don't baby it.

Well I'm stuck with 4 gears (A4LD) LOL.

I thought about regearing to 4.10's for the larger tires, but not possible thanks to the Dana 28's complete lack of aftermarket support. I don't need to upgrade/swap axles I don't have any need for that for driving on the highway most of the time, and for what I do off-highway I don't need stronger axles, just better gearing to handle the larger diameter tires thanks to the tire manufacturer's lack of support for older vehicles. Cars today have 20+" wheels and the same ground clearance my 30+ year old 2 wheel drive pickup has with 14" wheels LOL.

Have to figure out where to get a Ring and pinion 4.10 gear set for a Dana 28...the 7.5" 4.10 gear set seems a bit easier to find.

 

[DCman]

I think so as well. I've been thinking about adding an LSD to my Bronco 2 lately as well. My Bronco 2 has 3.73's in it. It doesn't do too bad but fuel economy has gone down quite a bit with the 3x larger size tires on it...Yes, I believe it originally had 205/70R15's on it, closest I had when I got new tires right after I bought it was 205/75R15's, they were cheap Starfire tires, and by cheap I mean cheap...supposedly a 40 or 50k tire, I managed to get 27k out of them and they were worn out and falling apart already LOL. I have Cooper Discoverer AT3 4S tires 235/75-R15's on it now. The speedometer is 5mph off no matter what tires it has, I think the speedometer is just screwed up in it to begin with. Broke the speedo cable in it, new one in it and it still sticks, and is still 5mph off so ehh LOL...however comparing the odometer from one side of town to home between the Ranger and Bronco 2 which was about a 4 mile trip the odometers between the 2 is only 2 tenths of a mile off, which makes no sense but whatever LOL. I just drive 30mph according to the speedometer when I need to go 25mph and its spot on. I have no idea what the PO did to that Bronco 2 but nothing was good that he did LOL.

I would like to add a LSD to my Ranger as well, but its about 100% useless in snow anyways without any weight in the bed LOL. An LSD in it wouldn't do any good with an unloaded bed, it spins both rear tires just fine in snow without an LSD HAHA!!

Ok, I calculated before on 3.45's, so this time I did some comparisons of 3.73's to 4.10's.
If you swap out to 4.10's, change your tires to P215/75R15's and you should be golden....if they still make off road tires in that size.

 

[DCman]

I have a 3.73

I have a 3.73 rear end , open differential. I'd like to have an e-locker and 4.10 gears in it someday.

Do you feel the 3.73's were still a little tall for the work you described in your prior post? (post #39 on page 3)

 

[cbxer55]

The guy that is going to do the gear swap on mine recommended Auburn Locker. I looked it up and sure enough, they have one for 7.5s. I just have to wait for awhile to get mine done. Lots of rain in the forecast, and that's why I have the Ranger to begin with. When I see a week of dry, I'll drop it off at his shop, walk home, and drive my Mustang or ride one of my bikes for a spell.

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[Roert42]

If you are swapping the gears, it's the same amount of work as swapping the carrier, you still have to reset the lash. The only thing you would have extra to do is press on a new set of carrier bearings.

If you pressed on the carrier bearings, and installed the ring gear on the carrier, it would actualy be less work to swap the carrier and the gears then just swapping the gears. Plus you wouldn't have to go back later and drain the diff to install the locker. Plus Plus, you would save money on tires not running a locker on the street.

 

[wildbill23c]

Ok, I calculated before on 3.45's, so this time I did some comparisons of 3.73's to 4.10's.
If you swap out to 4.10's, change your tires to P215/75R15's and you should be golden....if they still make off road tires in that size.

That's why my Bronco 2 is sitting on 235/75R15's, nobody has the right size tires anymore for them....at least nothing in a snow rated tire, yeah you can find a few all season tires but I want 1 tire that'll handle the snow/ice and backroads. The Cooper Discoverer AT3 4S tires on the Bronco 2 now handled the snow/ice this winter very well and I bet if I aired them down a bit they would do even better, but didn't get but 1 snowstorm this winter that required a little 4WD use and it was 10 inches of snow so I never had a chance to air down and try that out, but at 40psi the tires had plenty of traction and in 4WD no tire spin at all, very little sliding on ice either...yeah sure if you just stab the brake as hard as you can like an idiot it'll slide of course but driving normally and modulating the brakes it does great. Would love to try in some deeper snow hopefully next season when I can go up north if they don't cancel the McCall, Idaho Winter Carnival again because of COVID...ugg... I have been here for 30 years, I have never been able to go to that carnival, I just mainly want to go to see all the ice sculptures, but I love the scenery up there in the winter too, tons of great photo opportunities.

I don't think I'll be doing any gear swaps as nobody makes 4.10 gears for the Dana 28, and I'm not swapping to a wider axle just for a gear swap, my Bronco 2 is stock so it'll go pretty much anywhere you can take one of those $30k UTV's and some of them I swear are wider than my Bronco 2 is now, don't want it any wider I like it as it is.

The 3.73's do OK, I don't drive it on the freeway anyways so its not that big of a deal running it at 65mph on the highway between home and Boise, ID and back, but any faster than that and no thanks LOL. My Ranger does the freeway at 80mph extremely well, and honestly haven't even taken the Explorer out on the freeway yet, no need to, don't drive to Boise very often, and there's nothing I need that requires use of the freeway. Which is one thing I don't understand why so many people keep moving here to Emmett, Idaho. Boise is 30 miles away, there isn't a freeway within 40 miles of Emmett no matter what direction you go, its all 2 lane highway, and backroads in and out of Emmett...and most of the orchards are gone being replaced with over-priced houses with no land house takes up the whole dang lot type thing with many of these new subdivisions....out north of town where I'm at an acre is as small as they'll divide, and I'm wishing I still had the 2nd acre from my place . Someday I hope to be able to buy it back, even if I keep the back house as a rental I want my 2nd acre back LOL.

 

[snoranger]

I don't think I'll be doing any gear swaps as nobody makes 4.10 gears for the Dana 28, and I'm not swapping to a wider axle just for a gear swap, my Bronco 2 is stock so it'll go pretty much anywhere you can take one of those $30k UTV's and some of them I swear are wider than my Bronco 2 is now, don't want it any wider I like it as it is.

You’d be surprised what those $20k UTVs can do... but yes, they’re pretty much the same width as a BII with almost a foot more ground clearance.

 

[wildbill23c]

You’d be surprised what those $20k UTVs can do... but yes, they’re pretty much the same width as a BII with almost a foot more ground clearance.

View attachment 56663

I had a UTV, wasn't impressed, my Bronco 2 gets better fuel economy, twice the power, a better 4WD system, and AC/heat from the factory as well as a cab and windshield wipers and a radio that no stock UTV comes with...yep Polaris has a UTV with a factory cab and everything, but you are paying $30k for it, and its not street legal...and its a Polaris no thanks LOL. I had a Yamaha Rhino 700. It was ok on trails, but for utility use it 100% sucked. I decided I'd rather have the Bronco 2 than another UTV, I can drive my Bronco 2 wherever I want across the country, have to haul a UTV wherever I'd want to go aside from up in the hills around my house that I can get to on the backroads, but I can just as easily jump in my Bronco 2 and drive up those same trails and not need a trailer to haul around a toy LOL. I think if I ever got another UTV it would be for pure utility use on the property rather than go up to the hills and play type stuff, so most likely a Diesel UTV like the Kubota RTV, or the John Deere Gator...probably the RTV though, won't do business with John Deere due to the dealer in my area. Right now honestly, my 87 Ranger does all the UTV stuff around my property just fine, so a UTV really isn't much use to me anyways at the moment, but never know what the future may hold, especially if I get a new Ranger in the next year or 2...a UTV may be the way to go at that point, as I think I'd get rid of my Bronco 2 and current Ranger and just have the Explorer and new Ranger.

Ground clearance has never been an issue, I simply just drive around the really nasty stuff LOL.

 

[snoranger]

I had a UTV, wasn't impressed, my Bronco 2 gets better fuel economy, twice the power, a better 4WD system, and AC/heat from the factory as well as a cab and windshield wipers and a radio that no stock UTV comes with...yep Polaris has a UTV with a factory cab and everything, but you are paying $30k for it, and its not street legal...and its a Polaris no thanks LOL. I had a Yamaha Rhino 700. It was ok on trails, but for utility use it 100% sucked. I decided I'd rather have the Bronco 2 than another UTV, I can drive my Bronco 2 wherever I want across the country, have to haul a UTV wherever I'd want to go aside from up in the hills around my house that I can get to on the backroads, but I can just as easily jump in my Bronco 2 and drive up those same trails and not need a trailer to haul around a toy LOL. I think if I ever got another UTV it would be for pure utility use on the property rather than go up to the hills and play type stuff, so most likely a Diesel UTV like the Kubota RTV, or the John Deere Gator...probably the RTV though, won't do business with John Deere due to the dealer in my area. Right now honestly, my 87 Ranger does all the UTV stuff around my property just fine, so a UTV really isn't much use to me anyways at the moment, but never know what the future may hold, especially if I get a new Ranger in the next year or 2...a UTV may be the way to go at that point, as I think I'd get rid of my Bronco 2 and current Ranger and just have the Explorer and new Ranger.

Ground clearance has never been an issue, I simply just drive around the really nasty stuff LOL.

This ones a 2016 Yamaha Wolverine 708. It’s great on trails, and awesome in mud (I’ve driven it through 36” deep mud), but it’s slow. Next year I’m planning on buying a YXZ1000r... the wife wants to keep the Wolverine too.

 

[dccarpenter]

Do you feel the 3.73's were still a little tall for the work you described in your prior post? (post #39 on page 3)

They definitely are , strangely enough only when towing. I can load the bed with 1400lbs of tools and supplies and the truck rides fine but the same 1400 trailer weight will be slow going up a steep hill. I wouldn't change the gears if I never towed but I move my boat around with the truck a lot and occasionally tow materials on long drives (8hr+).

 

[wildbill23c]

This ones a 2016 Yamaha Wolverine 708. It’s great on trails, and awesome in mud (I’ve driven it through 36” deep mud), but it’s slow. Next year I’m planning on buying a YXZ1000r... the wife wants to keep the Wolverine too.

Same setup honestly that my Rhino had, a permanently locked rear differential which destroys your yard that was one huge negative for it, and the very limited cargo capacity in the bed unless you wanted to lift it yourself, they claim 400 pounds, it won't lift that with the gas assist strut, you want to haul that much you will have to lift the bed up to dump it yourself LOL. Yamaha I think has the best CVT out there as far as durability, and the ability to give you full engine braking. My Rhino only had a 686cc engine, to these newer Yamaha UTVs have slightly larger engines for the most part, until you get into the YXZ1000r you mentioned with has almost a 1L sized engine. My Rhino had a single cylinder engine, I think some of the newer Yamaha UTV engines are 2 cylinder engines. I think the top speed on my Rhino on a good day on flat ground was 45mph....plenty fast enough for a 4WD go kart LOL. Kind of what that thing seemed like really out on trails was a 4WD lifted Go-Kart. Anymore the only thing I really would want one for would be yard work type chores, so more utility use in mind which led me to thinking about the Kubota RTV diesel, especially if I am able to get the 2nd acre back once the family decides what they're going to do after their mom passes away, I don't think they're going to be keeping it because none of them live in the area and its more of an eyesore because she decided she wanted a studio. So when she inquired about it, we thought she was talking about just a simple shed type thing to use for her art/painting. Nope turned into a full blown 2nd house back there, how she got away with that on an acre is beyond me. If I got the property back, I think I'd demolish that 2nd house, and rent out the 1st one possibly, or just remove both and turn it back into pasture which is really what I would rather do. I'd rather mow it or keep a horse or cow or something out there. Renting out the one house would probably be ok if I could get things straightened back out on that property since its been torn up so bad....so if I do that a UTV would certainly become an asset to me again but until then I'll keep running my Bronco 2, its pretty fun as it is really because of its size it'll go darn near anywhere on those trails.

 

[19Walt93]

The guy that is going to do the gear swap on mine recommended Auburn Locker. I looked it up and sure enough, they have one for 7.5s. I just have to wait for awhile to get mine done. Lots of rain in the forecast, and that's why I have the Ranger to begin with. When I see a week of dry, I'll drop it off at his shop, walk home, and drive my Mustang or ride one of my bikes for a spell.

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Experience the thrill and ease of tailoring your Truck or Jeep with our Guaranteed Lowest Prices on all Ford 7.5 Inches Ford Auburn Gear Differentials products at 4WP. Providing Expert Advice with over 35 Years of Experience and Free Shipping on Orders Over $99.

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I'd recommend against an Auburn. I've had an Auburn Pro in my Mustang's 8 inch for over 20 years, the first one wore out and Auburn replaced it. The biggest problem is the limited slip is a metal cone in a metal cup and it sheds metal particles into the oil. How well do you like replacing rear end bearings?

 

[cbxer55]

More than likely I'll just get the 4.1 gears and have my friend's shop rebuild the stock unit. I do believe it needs some spiffing up after 23 years and 174,000 miles. Should be good after that. Whenever I make a hard right turn, I'm getting some noise from the axle. Forward or backing up. Loud enough that my almost deaf ears hear it. It's not the front end, that was rebuilt in it's entirety in July 2018.