3.73 vs 4.10 gears - fuel economy?

[racsan]

sounds like worn spiders

 

[cbxer55]

sounds like worn spiders

Could be. Weird things have been happening while making hard right turns in town. They're full of salt and sand from the last winter storms we had. It's all pushed over close to the curb. The other day, going around it, when the right rear t ire hit the glop, it started spinning while the truck practically came to a standstill. I know it's an Open differential, but I don't believe that is normal. So yeah, will have Rick rework the carrier and put the 4.10s in there while he's at it. I think that'll be good for a bunch of years, or however much longer the thing runs. LMAO!! (Still running awesome btw)

 

[DCman]

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+).

Interesting comment.
I was sure you'd definitely be yea or nay.
Never heard that about towing a trailer before. Could it be roll resistance from the tires, and/or dry bearings, and/or dragging brakes?
Have you tested that trailer by towing it empty? If it still drags the truck down (not nearly as much as loaded, of course), there's part of your problem right there.
Anyway, thanks for the benefit of your experience. I've definitely been given something to think about.

 

[DCman]

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.

I was going to suggest Super Swamper TSL/SSR Radial 27x9.50R15's, but if you wanna stick with what you have, that's fine.
One of my nephews used to work at that resort out in McCall a few years back. Ended up managing the restaurant portion, then took over a sushi place that was also in McCall. Had to come back here because his girlfriend's dad got sick.
I think he works in Seattle now.
...and thank you for getting the "You-don't-have-to-go-60mph-on-every-road" concept.
I tell folks not from here that I (and most people who grew up around here) are happy doing 60 on the freeway, especially since I only use it when I'm running late.
They're like I'm like
Right on, brother.

 

[wildbill23c]

I was going to suggest Super Swamper TSL/SSR Radial 27x9.50R15's, but if you wanna stick with what you have, that's fine.
One of my nephews used to work at that resort out in McCall a few years back. Ended up managing the restaurant portion, then took over a sushi place that was also in McCall. Had to come back here because his girlfriend's dad got sick.
I think he works in Seattle now.
...and thank you for getting the "You-don't-have-to-go-60mph-on-every-road" concept.
I tell folks not from here that I (and most people who grew up around here) are happy doing 60 on the freeway, especially since I only use it when I'm running late.
They're like I'm like
Right on, brother.

The tires I have now do great in snow/ice, that's why I have them. Super Swamper tires are NOT for snow/ice LOL. People around here had to learn that the hardway with their lifted trucks when they'd end up in the ditches every snowstorm because they had no control over their vehicles. Those tires become skis in snow/ice.

Most of the speed limits around this area are 55mph or less, in town they're 20-30mph for the most part so no need to worry about needing to drive 55mph+ and I have my Ranger and Explorer if I need to go on a longer trip out of state or something anyways. If they had options to regear the Bronco 2 I'd do it but there's nothing out there and not worth swapping axles and making it look ridiculous with wider axles on it. I daily drive my Bronco 2, it needs to be street legal, swapping axles that are wider would actually make it illegal if the cops want to get bored and start ticketing people for it.

I haven't been to McCall for 15 years never had the chance to go. I need to and it would be a nice trip in the Bronco 2 in the winter.

 

[cbxer55]

Ordered the 4.10s and a differential carrier from Motive Gear a few minutes ago. Soon as I get them, I'll drop the truck at my friend's shop down the street. Right now, he's building a Turbo 400 for a friend, who is puttin it in a 49 Ford COE, Cab over Engine. Believe it is designated F6. Gonna be one cool ride when finished. He's actually put the body of the F6 onto a late model GM dualie platform. Will have a 396 with aforementioned Turbo 400.

 

[8thTon]

I honestly don't think I'd want a limited slip. When a wheel spins on a open diff you have the other wheel to keep the back end located sideways. I find that if I have weight back there it has fine traction.

 

[cbxer55]

I honestly don't think I'd want a limited slip. When a wheel spins on a open diff you have the other wheel to keep the back end located sideways. I find that if I have weight back there it has fine traction.

The Motive Carrier I bought doesn't specify what type it is, therefore I assumed it is a replacement Open carrier. The price wasn't high enough for me to believe it is a LSD or Locker. I'm fine with that. Mainly want the 4.10s. And since it seems the issues I am having could be worn spider gears, figured a new Carrier was the best route.

 

[cbxer55]

Someone school me, I'm confused. The speed sensor on the 98 Ranger is on top of the differential. I'm assuming it reads the ring speed. So, got the truck back today with 4.10 gears. Odometer didn't change, it still reads one mile between stop signs and lights here., just like it always has. Speedometer seems to be the same, but the rpm's are higher.

I'm assuming when you go from 3.73 to 4.10, the only thing that changes is the pinion has less teeth. The ring is the same o.d., but the tooth shape changed to match the new smaller pinion. If the speed sensor is reading ring speed, then it would make sense that nothing changed. The sensor being on the axle, apparently it doesn't use gears, has to be changed via a scanner.

Where am I wrong? Because I expected to have to order a handheld tuner to be able to alter things once the gear change was done. Noting but engine rpm changed though.

 

[snoranger]

The sensor reads the ring gear speed. The ring gear has to spin at XX RPMs to turn the tires at XX RPM. It doesn’t care what RPM the engine is at to get there.

 

[cbxer55]

The sensor reads the ring gear speed. The ring gear has to spin at XX RPMs to turn the tires at XX RPM. It doesn’t care what RPM the engine is at to get there.

So you're saying my fuzzy thinking on the subject is correct? If the sensor was in the transmission tail shaft as they usually are, it would've needed to be adjusted. But being in the differential, it doesn't care. Nice.

 

[snoranger]

So you're saying my fuzzy thinking on the subject is correct? If the sensor was in the transmission tail shaft as they usually are, it would've needed to be adjusted. But being in the differential, it doesn't care. Nice.

Yes.

 

[Roert42]

So you're saying my fuzzy thinking on the subject is correct? If the sensor was in the transmission tail shaft as they usually are, it would've needed to be adjusted. But being in the differential, it doesn't care. Nice.

On that style only if you change tire size.

 

[RonD]

Yes, 1998 to 2000 Rangers used the ABS sensor on rear axle for speedometer/odometer, it registers AXLE rotations per mile
So ring gear tooth count(or pinion) won't matter, but tire size will matter

Drive shaft speed needs to be converted to rotations per mile using tire size and gearing
3.73 means drive shaft rotates 3.73 times for each 1 time the axle rotates
4.10 would rotate 4.1 times for each 1 rotation of the axle
And then you need to know how far vehicle travels with 1 turn of the axle which varies by diameter of the tire

Yes, "higher" ratio number means drive shaft must turn more for each 1 full turn of axle, so engine RPMs would need to be higher to maintain the same speed with a 4.10 vs 3.73

"Lower" ratios can give better MPG if highway driving is what vehicle does mostly, because RPMs are lower at say 65MPH than with a "higher" ratio, but...................
Its also about the engine and its best economy RPM, in general an engine is most efficient 300-400rpms below its peak torque
So if engine makes best torque at 2,500rpms, then 2,100-2,200rpm would be best RPM cruising in OD
If you drop to far below best torque then you would have to press the gas pedal down more to maintain speed, you are in essence "lugging" the engine so MPG goes down
So its not all about lowest RPM when cruising

 

[cbxer55]

It just doesn't seem to make as much difference as I thought it would. But oh well, it's done. Doesn't have a tach, so I am only going by the ear tach. Eventually going to add another wart to the hood, with a hood tach.