Re-gearing diff advice

[tnine]

Hey guys,
I've almost completed my build. I have my lift, 285/70/17 tires, wider wheels and a winch. I'd like to re-gear my differentials to get more torque. I have a few questions.

I have a 2014 4Runner SR5. According to the parts department at the dealership, I have a 4.11 gear ratio from the factory, is this correct?

Using rough country's diff calculator, I need to go to at least a 4.375 ratio to get back to "factory power". I don't mind sacrificing a bit of gas milage and top end speed to have more torque. What sort of ratios have you guys gone up to, and what's your highway driving experience like? I'm thinking if that is the correct ratio, I'd like a bit more torque than factory.

Can someone explain to me how this is calculated? I'd love to know.

I'm not sure I really have the need for ARB lockers, my a-trac has sufficed so far. Is it possible to simply change the ratio of the existing factory diffs with new gears, or do I have to buy aftermarket lockers?

Cost is an issue, so I want to weigh my options. For a full ARB setup I'm looking at 4k, and I don't really envision doing anything hardcore enough to need them for at least a few more years.

Thanks in advance!


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[Engineer]

3.73 from the factory

 

[3wbdriver]

And I THINK 4.56 is your only option.

 

[Swarty]

You can go lower...

And I THINK 4.56 is your only option.

There is also a 4.88
In case you wished you'd bought a tractor or have some way of running 37s.

 

[Jeremy556]

And I THINK 4.56 is your only option.

Nitro has 4.88s out now, too. Can also do 3.91 with Toyota gears but they are pricey

 

[Jetboy]

3.91 is probably cheapest because you could buy a used set out of a wrecked GX460, but the jump from 3.73 to 3.91 probably isn't worth the effort. 4.10 would be ideal IMO for 285s, but there are no 4.10 or 4.30 gears for the 4runner.

The way it's calculated is by how many rotations of the pinion gear (drive shaft) it takes to make one rotation of the ring gear (tire). So a 4.10 ratio has a 10 tooth pinion and a 41 tooth ring gear. A 3.73 usually has an 11 tooth pinion and 41 tooth ring gear. Unfortunately you can't mix and match a 10 tooth pinion with a 41 tooth gear for a 3.73. The teeth are cut differently.

 

[v_man]

I'd go 4.56 , you'll be set if you ever want to go up to 35's , or if you want to bolt on a bunch of weight . Don't waste your time by not going low enough , the first rule of re-gearing is you only want to do it once.

I'm a big ARB fan , $4,000 is a lot but front and rear selectables is...

 

[wfo9]

4.56 is really your only choice. With 285s its a little high strung on the hwy, but not a big deal. Your mpg will go to total crap above 75mph though...

34s(315s or 305s) will drop the rpm a bit and then true 35s will take it back to near stock characteristics (but I doubt you would ever be running those).

Offroad with 285s, you will notice a huge difference in control. The truck will walk over stuff without even touching the gas and your speed will be much more controlled when you are descending and holding first gear. The tq converter will flash way less also... Overall, just way more control of the power.

If you don't have a factory rear locker.... I would highly recommend that you take the plunge and put an ARB in the rear at the same time. ATRAC is OK and can get you out of most situations, but that rear locker is really mandatory when you start pushing things. ATRAC can get really sloppy and put a lot of stress on things in tough terrain. The front is much more of an optional thing that most people don't need or want to bother with managing (it can get you into major trouble without steering, or POP a CV...). Gears without lockers is OK I guess, but it just seems odd to add them without having the complimentary equipment. Sort of like adding a huge lift and running stock tires..... Plus since you have the 3rd member out anyway.. It just seems like a waste not to put it in....

 

[gm350reratliff]

Gears are on my list as well. Does anybody know if the 4.30 gears offered in the Tacoma would work in our 4Runners? To me, 4.10 is not enough and 4.56 is a bit too much but 4.30 seems to be what I need.

 

[1engineer]

Gears are on my list as well. Does anybody know if the 4.30 gears offered in the Tacoma would work in our 4Runners? To me, 4.10 is not enough and 4.56 is a bit too much but 4.30 seems to be what I need.

They will not work. The only ones available are the ones the guys listed above.

 

[tnine]

Thanks for all the feedback guys. I spoke to Ben at Slee off road today. He was recommending going to a 4.56 diff, as well as going to a 265 or 275 Goodyear wrangler to reduce tire size and weight. He feels this will give me the best torque for better power, and keep my fuel consumption reasonable.

What are your thoughts on this?


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[rochmpr]

4.56 with 285/75's (34") tire is about as close to stock as you can get. Actually a little more on the bottom end. This Combo equates to a 7% lower gear than stock. The smaller the tire, the larger the difference.

 

[1engineer]

Thanks for all the feedback guys. I spoke to Ben at Slee off road today. He was recommending going to a 4.56 diff, as well as going to a 265 or 275 Goodyear wrangler to reduce tire size and weight. He feels this will give me the best torque for better power, and keep my fuel consumption reasonable.

What are your thoughts on this?


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You won't get better power as you say. You will get more torque. You will drop efficiency running stock size tires with 4.56's. Do you want more torque? If so then do it. Do you want better efficiency? Stock size tires and stock gearing. Your choice.

If you run bigger than 285's then 4.56 will help efficiency and bring torque back close to stock values.

 

[flyinhawaiian01]

What exactly are you trying to accomplish with your vehicle? It makes no sense going back to a stock sized tire (265/75r17 is oem size) and re-gearing the vehicle, as you'll only gain torque at the expense of rpm at 60+mph.

There's a trade-off for lifted trucks with bigger tires, and that's fuel consumption and peppiness at all speeds, that's just the fact of life. Trying to re-gain that torque and mileage by doing gears is great, but re-gearing with stock tires, or something so close as a 275 or 285 series tire, just makes no sense to me, especially with a (dare I say it!) decent 4 litre V6!

My take on this is that you probably like the lift kit and the way it looks with the 285's on there, and being that you have a winch already, I can assume you'll be using this for the trails sooner or later, if not already. Keep the tires, install the gears, call it a day!

And, if its any consolation, having 4.56 gears in there already, you'll be ready to go another size up in tires without too much degradation in power.

And for the record, your gears, according to the 2014 product info guide from toyota, your stock gears in the diffs are 3.727, generally speaking, you're going down 3 gear sets (had toyota made a 3.92 and 4.10 set for the new diffs), that's quite similar to what us 4 bangers have been doing for many years! Most of the older toyotas came with 4.10 sets and stock tire sizes of 30-31" tires. For me, I went to 35's and 4.88 gears, and its a good balance with what it is. Its not a race car, even though I sometimes drive it like one, and it still gets 21mpg if I drive like grandma!

Do the gears and see where it goes from there if you really need to gain some performance back from doing the lift and tires. Just understand that highway speeds are going to be clocking a lot higher rpms, especially with 265's~285's!

Btw, going from 265's to 285's is only a 6.6% change in revolutions, yet your rpms with the different gear set is almost a 20% reduction.

 

[Jetboy]

FWIW the 6th gear rpms range varies dramatically in the new tacoma depending on MT or AT. In the 6 speed MT version with 4.30 diff gears, 80mph = 2,750rpms. In the AT version with 3.73 gears 80mph =2,000rpms. There's a 35% difference in RMPs at highway speed between the manual and auto versions. That's a big difference!

With 285s and 4.56 gears, you'd nearly identically match the gearing at highway speed of a stock manual transmission 2016 tacoma. It's not a direct comparison as the 3.5L is more comfortable at higher rpms and can actually decrease its displacement so it can run like a 2.5L engine. Possibly that gives it a big advantage in efficiency at high rpms. But just something to give a comparison.

 

[Mile high]

Also considering regearing my 5th gen

I'm also considering re-gearing my 5th gen LE. I currently have it lifted (Toytec Boss) have added sliders and 285 70 17's. I've just about to decided to add F+R ARB Lockers but struggling with the gears. The stock gears are still sorta ok even with 285's. I live in Colorado and even going up the mountain isn't too bad, just have to hammer it. Like many, i do mostly city driving and some highway away from the mountains. I would go with Nittro 4.56's but only concern is need to drive 75 -80 at times and the extra RPM's and mileage loss in those situations. Ie. a road trip to Moab for example....would i regret the lower gears? I guess you can't have it all but would love to hear directly from someone who has regeared and if the HWY performance has prompted any regrets?

 

[TravelWest01]

I put 4.56 Nitro gearing in last year, along with ARB lockers. The gearing made a big difference at low speed, my 4Lo 1 is an amazing crawling gear. I go up and down just about anything without touching the brakes. On the high end, I comfortably cruise at 75 and can pass as needed. With my lift and 285s the mileage didn't change, it was 13 before and 13 after. Bottom line, don't fear the gear!

 

[jmf_tracy]

4.56

FWIW, i am running 285-75-17 and re-geared to 4.56 Nitro.
I am very happy with it and could not imagine going bigger or smaller on the gear size.

 

[Mile high]

Thanks so much! Good to hear from people who have actual experience with a particular mod vs opinions or 3rd party feedback etc. Nothing worse than shelling out close to 4k and end up disappointed. Appreciate the feedback.

 

[Swarty]

Improved my mileage.

I would go with Nittro 4.56's but only concern is need to drive 75 -80 at times and the extra RPM's and mileage loss in those situations.

Slight mileage improvement which I guess is mainly because I'm not hammering it to get what I want. Cruise control can function without sudden downshifting. Off road has way more control. Highly recommended.