4.56 Gears On Mostly Stock Build

[nicholas.craft]

I hear you on struggling to keep the 4runner. I love them so much, but for 2020 we need at least a reflash of the transmission shift points or something like 4.10 option from the factory. Driving this thing in the mountains unless you want to keep it floored the entire time makes me feel like those semis that get in the car right lane and turn on their flashers. I've been looking really hard lately at the ecodiesel JKU or now the new Bronco. Although both awesome vehicles, I love the bullet proof nature of the 4R and that's what's always drawn me to them. I really hope the 4R 6th gen blows the world's socks off because with the war about to take place between Ford and Jeep it could easily get left way behind!

 

[Jetboy]

IMO - nitro is wrong on that opinion. 4.10 is a big difference from 3.73. It's more different from 3.73 than 4.88 is from 4.56. If you were going to drop a ratio - 4.88 would be the one to drop and just to a 4.56 and 5.29 set.

 

[nicholas.craft]

Appreciate the input. I wonder why everyone is so opposed to offering 4.10's? In my original research it did seem like it would be darn near perfect for stock or 32 inch tires.

 

[nicholas.craft]

FWIW, I'm in on a group buy if someone is willing to make a 4.10 set for the 5th gen as long as it doesn't exceed $1,600 ish.

 

[Jetboy]

Assuming this is commonly known - but Toyota does make 3.91 ratio. To Toyota at least 3.91 is enough different from 3.73 to justify. I'm a little more skeptical of that decision. And I don't see much value for us in swapping to the 3.91 ratio. I'm still not totally sure why Toyota chose to make that extra ratio.

Toyota at one time made both 4.10 (41 tooth ring gear and 10 tooth pinion) and 4.11 (37 tooth ring gear and 9 tooth pinion) ratio 8" differentials. Why you'd ever do that is beyond me to even take a guess at.

As far as cost - I really have no reference to even guess what a small batch order would be. A typical gear retails for about $200-250, but I wouldn't hold my breath on it unless Toyota decides to put it in a model. The cost is mostly in the labor to install. And in our case - it's mostly just the huge PTIA it is to swap the carrier. Setting up a rear diff only takes around an hour or so. A front is more of a PITA, but maybe 2 hours. The removal and install takes me about 5 hours in the back and probably 5 hours in the front on my garage floor without a vehicle lift.

 

[tls3601]

The FJ40 had 4.10 gears up until 1979 when they went to 3.73 claiming it would improve MPG. It didn’t as friends who had ‘79-83 40’s claimed no mileage improvements BUT did not like it as much off road. As a matter of fact many guys who purchased ‘79-83’s would immediately regear or swap out to older axles. I wonder if the ‘84-85 4Runner with solid front axle came with 4.10? 3.73 just seems wrong and limits vehicle as to tire size and off road performance.

 

[tls3601]

Gearing can make SUCH a difference. 4.10 seems as though it would be perfect on our T4R’s

 

[delloro]

From the sounds of it these things shouldn't have even left the factory with 3.73 gears.

CAFE standards.

 

[rayofsi]

so i finally got on 285/75r17 nitto ridge grapplers

its slightly slower then with 275/70r17 and less peppy
but i think this is still ok.
4.10s i'd probably jump on for the extra pep

4.56 maybe too much.

i do have a supercharger installed.

 

[nicholas.craft]

How are you liking the supercharger (probably a dumb question)?

Also, would be curious if someone on here with 4.56 gears could throw on stock tires and give us a 60 and 75mph rpm check? Wonder what the MPG hit would be with 255/75r17 tires. All the questions I have are what makes it hard to pull the trigger on gears even though I think that's all I need. The supercharger I know exactly what I'm getting a d it's easier to rationalize what the feel will be. Basically the same tons and fuel economy I have now with the opportunity to put the peddle down for an extra 80 ponies and torque.

 

[TNTOVERLAND1]

4.56 gears

I have a 2020 trd pro and have regeared it with 4.88's its a little deep for a lot of hwy driving unloaded but I love them I pull a patriot camper with it all the time and live in Utah it was horrible with out the re gear. my 4 runner is stock everything. at 80 mpg Im at 3k rpm do the regear for sure it was a huge improvement I plan in putting 285 tires on it and then it will be perfect

 

[nicholas.craft]

I appreciate the real world response! Sounds like 4.56 on 32's wouldn't be all that terrible at 75mph.

 

[spartacus]

You can play around on this site and the numbers are pretty close to real world.

Gear Ratio Calculator

 

[Jetboy]

How are you liking the supercharger (probably a dumb question)?

Also, would be curious if someone on here with 4.56 gears could throw on stock tires and give us a 60 and 75mph rpm check? Wonder what the MPG hit would be with 255/75r17 tires. All the questions I have are what makes it hard to pull the trigger on gears even though I think that's all I need. The supercharger I know exactly what I'm getting a d it's easier to rationalize what the feel will be. Basically the same tons and fuel economy I have now with the opportunity to put the peddle down for an extra 80 ponies and torque.

At 70mph, stock gearing and tire size in 5th gear with torque converter locked, 1988rpm.

70mph 4.56 gears and stock tires size 5th gear tc locked = 2430rpm.

70mph 4.56 gears and 32.8 tire = 2322 rpm

70mph 4.56 gears and 34" tire = 2259 rpm


Where I found it to be an issue is higher speeds and when you drop into 4th gear with 4.56.

80mph stock ratio and tires= 2253

80mph 4.56 and 32.8 tire = 2653



75mph 4th gear all stock = 2776

75mph 4th gear 32.6 tire = 3503


Now - what matters with this in fuel economy is the thermal efficiency at power and rpm.

This is the newer Toyota v6 GR engines. And what's overlaid here is the new atkinson cycle efficiency vs the old one. What's really important is how much the new engine expands the efficiency RPM ranges. But if you look at the older map underneath - it's still the 3.5 that's efficient at higher rpms. So it's still not totally representative. BUT with all those conditions, what you'll see is that the efficiency likely in ours drops off a pretty major efficiency cliff when you get beyond 2300 or so rpms. In our case I think it's really more like 21-2200 rpms is where that decline happens. By 3k rpms it's dropping very fast.

That's why people who are in areas typically driving at 80mph probably see a much greater mpg hit than people who are driving at 65mph most of the time. It's not just the higher wind resistance. It's that the engine is being pushed outside of it's thermal efficiency range.

If we had a good map for the 1GR (I'm not aware of anywhere to find one), then we could probably estimate pretty closely exactly what would happen with any gearing and/or tire combo.

 

[mo_mo]

At 70mph, stock gearing and tire size in 5th gear with torque converter locked, 1988rpm.

70mph 4.56 gears and stock tires size 5th gear tc locked = 2430rpm.

70mph 4.56 gears and 32.8 tire = 2322 rpm

70mph 4.56 gears and 34" tire = 2259 rpm


Where I found it to be an issue is higher speeds and when you drop into 4th gear with 4.56.

80mph stock ratio and tires= 2253

80mph 4.56 and 32.8 tire = 2653



75mph 4th gear all stock = 2776

75mph 4th gear 32.6 tire = 3503


Now - what matters with this in fuel economy is the thermal efficiency at power and rpm.

This is the newer Toyota v6 GR engines. And what's overlaid here is the new atkinson cycle efficiency vs the old one. What's really important is how much the new engine expands the efficiency RPM ranges. But if you look at the older map underneath - it's still the 3.5 that's efficient at higher rpms. So it's still not totally representative. BUT with all those conditions, what you'll see is that the efficiency likely in ours drops off a pretty major efficiency cliff when you get beyond 2300 or so rpms. In our case I think it's really more like 21-2200 rpms is where that decline happens. By 3k rpms it's dropping very fast.

That's why people who are in areas typically driving at 80mph probably see a much greater mpg hit than people who are driving at 65mph most of the time. It's not just the higher wind resistance. It's that the engine is being pushed outside of it's thermal efficiency range.

If we had a good map for the 1GR (I'm not aware of anywhere to find one), then we could probably estimate pretty closely exactly what would happen with any gearing and/or tire combo.

Maybe URD has curves for the 4.0L... they seem to have given up on CARB cert of their in-house supercharger, so maybe they're willing to share more dyno info.

 

[JLTD]

I don't know that I'm keeping my 4Runner a lot longer. But it's still not totally decided yet. I tried 4.56 and took them back out because I didn't like how low my mpg was on the highway. So my logic is that I'll just switch to a GX with the extra overdrive gearing and maybe then go 4.56. For the 4Runner I felt 4.56 was too deep of a gear for a small tire size change and 4.10 would be a better fit. But of course there are no 4.10 gears available....

Wondering what mpg hit you took on the highway? Did the 4.56 set keep you in 5th all the time?


Seems with the stock gears plus the slightest hill it drops down to 4th....here in the Denver area that means either locking it in 4th or watching the tachometer dance. I can only imagine how much heat is being generated with sometimes 5-6 shifts every minute.

 

[Jetboy]

Wondering what mpg hit you took on the highway? Did the 4.56 set keep you in 5th all the time?


Seems with the stock gears plus the slightest hill it drops down to 4th....here in the Denver area that means either locking it in 4th or watching the tachometer dance. I can only imagine how much heat is being generated with sometimes 5-6 shifts every minute.

The 4.56 did not keep me in 5th. I ended up in 4th less often, but still frequently. Towing my small camper I lost around 2-3mpg. I thought it would improve, but the result was around 11-12mpg towing vs 13-15mpg towing with stock gearing. Mostly because 4th gear with 4.56 ends up I think putting the engine too far outside of the efficient rpms range. It's possibly that even lower gears could have been better.

Around town it was probably pretty similar. On the highway empty I probably also lost 2-3mpg. With stock gears and an basically stock empty 4runner with only 33" tires and a 2" ish lift - I can still pretty routinely see 18-19mpg on the dash, so close to 20mpg after adjusting for tire height. With the 4.56 I was more like 16.

I think the engine is not properly tuned for high rpm efficiency, but rather is tuned to run rich and cool. So there's probably a lot of potential to be gained from something like URD's stand alone fuel management system. But is the juice worth the squeeze? Not for me. I'd rather just bump up to a v8.

My main thought was that if I'm going to live with 16mpg - I'd maybe rather have a vehicle with power that would be appropriate for a vehicle that gets 16mpg rather than try to fit a square peg in a round hole (make a 1GR fuel efficient at high rpms).

No question at all that the driving experience was better with 4.56. Everywhere. In town. On the highway. Towing. All more enjoyable in terms of power delivery. Unfortunately the noise and vibrations get worse. If I lived somewhere that didn't require routine 100-200 mile highway segments to camping areas, I'd probably prefer the lower gears. As it is - I spend a lot of time on the highway. This summer so far I'd guess I've towed around 2000 miles. Next week we're doing another long trip from Utah up to the Canadian border and will probably knock out another 1500 or more miles on that trip. I think I'm just trying to do too much with the little engine.

 

[Turfboy]

For a one-off, it's probably easier just to swap a housing for a 9.5 land cruiser and find an OEM rear e-locker axle with 4.10 gears. Those are pretty easy and cheap to find. For a group buy - maybe it'd be cheap enough to make it worth it. I think wholesale price is typically around $100 for a ring and pinion set, but I'm guessing the minimum order is pretty big if you have to cover the cost of new forging dies or you have to pay a big up front design/tooling fee.

Will both the front and rear housings swap or would you have to go with the whole package? :ballchain:

 

[Jetboy]

Will both the front and rear housings swap or would you have to go with the whole package? :ballchain:

Just the rear. Front 4.10 ratios are pretty common in Tacoma models. The front differential has 3.73, 3.91, 4.10, 4.30, 4.56, 4.88, and 5.29 ratios available.

It's the rear 8.2 that's the oddball. And it's only in the 150 platform. I believe the only ratios available are 3.73, 3.91, 4.56, and 4.88. I've searched a pretty good sample of various different country options to find a Prado 150 with a 4.10 diff ratio, but have not found one anywhere. Doesn't mean they don't exist, but I can't find a part number for an OEM set and haven't ever seen an aftermarket option.

The Tacoma jumped up to a 8.9" rear diff, the Fortuner and Hilux also have the 8.9" rear diff. Odd that Toyota puts the 8.2 in the heavier larger prado and GX460, but uses the 8.9 in the Fortuner. I assume the next iteration of 4Runner will also share the 8.9" rear diff. The 8.9 has many more ratios available as well. It comes in 3.73, 3.91, 4.10, 4.30 OEM ratios and I think at least 4.56, 4.88, and 5.19 aftermarket ratios.

If you went to a LC 9.5 rear diff, there's almost any option you can think of. Bolt in housings are available from a few places. But you're spending a lot of $ for that gear change. I'm not sure it's worth it. And I don't really know whether that's a better choice than a Dana 60 or Ford 9" rear axle option.

The 8.2 is pretty strong as well, so there's not really a need to go up in size for strength. It's just missing some ratios in the middle.

 

[Turfboy]

Humm, 3.91 may fill the bill with a URD SC. What is the vendor? Yukon?