Gears and beers

The title is basically click bait, but rest assured I am drinking a beer as I type this. So you've got your monies worth.

I need advice on a few aspects as I prepare for a differential rebuild.

The first one being wtf rear end do I have?!? I have dig around here, the rest of the intro webs, and even through parts departments and have gotten a different answer every time. I have a 2007 trd off road (w/elock)
Rear end code A04B. If someone could tell me the actual size and ratio I would greatly appreciate it as that will lead us into the next question.

Any advice on affordable ring and pinions as well as rebuild kits? I'm not trying to blow my load and spend $1k plus on this and will be doing the work myself along with my friend who is a master mechanic.

Lastly, should I go up in size? I eventually plan to run at least 33's if not 35's. But that won't be for some time down the road. I don't plan to do much in the way of loading down the vehicle with overland gear. But I have considered a bed rack and lighter weight rtt, that would be off the vehicle unless I am going camping. The only thing about changing ratios right now is that I would only be able to do the rear and would then tackle the front sometime this fall before winter hits. And I know that's kinda risky, but I'm a loner Dotty, a rebel.

All jokes aside, any and all advice, info and input would be much appreciated. Even the shit talkers are welcome!

 

8” open differential
All Off-roads were with e-locker were 8”. 3.72 ratio

I can’t help with tires and hearing.

 

Thanks! I appreciate this info!

 

You’re gonna get replies from people who struggle to do an oil change, saying gears are hard, and as hard as rebuilding an engine. Which I’m not sure I get the meaning of, as rebuilding an engine is easy.
Everybody starts somewhere, and there’s a first time for everything.
At $500-700 per axle labor, you’d be saving money.
however, it is still expensive. ARB air locker is $1000 per axle. Set of gears shims bearings etc about $1k.
So like 3k DIY?
I think ECGS is $3-4.2k and they mail you the cores pre built. So at that point, why not. Especially with their warranty. And the simplicity of bolting in something already pre assembled.

is it really worth spending time and money to save a buck in fuel, and not go all the way with lockers?
I am facing this same dilemma.

many actual off road trucks come with 4.10. You can find those used. I have some I may be willing to sell but they’re from an 8.4 carrier and may not fit your truck.
I believe we all have 8” front IFS clamshell.

mine is manual so ratios may differ from auto.
There is 4.10, 4.30 in FJ, 4.56, 4.88 etc to pick from
I hear for 33 or 35 you can use 4.10 or 4.56
I wonder if you can just swap in a bunch of parts from a crashed FJ.
I imagine 4.88 is too much unless it had armor and a house on the bed.

ARB has a video explaining air lockers to be the best. That the constant high PSI of air pressure can activate/deactivate it any time, and that more expensive e lockers like Harrop/Eaton cause a lot of heat from the magnet being energized.
Automatic lockers may have bad road manners especially in poor weather, which may be why they’re cheaper and used more on dedicated off road rigs getting trailered to a trail and not daily driven.

auto companies often are cheap and do the bare minimum. Therefore if they chose to use electric locker technology that probably means it’s somewhat bad and not the best thing to want/try to upgrade to

stock ratio 3.73 is a joke. My sedan was 4.10 with a smaller engine and car tires. Gladiator rubicon comes with 4.10 as does old 3rd gen T4R OR.

don’t know what to think about tires. I know if I listed my almost new set of Wildpeaks (probably $1k) some guy on Craigslist is gonna call “I gihya bout tree fiddy. No not $350. $3.50”
If I could sell them for 2/3rds, great, 33->35. But if not, might be stuck with them for a while. They don’t seem to be wearing fast at all. Load E. Any time I measure tread it stays deep as hell. Like 14/32”

I don’t see why you can’t do one at a time and simply keep it in RWD until they both match

 

Unfortunately, the size (8, 8.4, etc.) Refers to ring gear size. So from my understanding, I have an 8 inch rear and an 8.4 will not fit.

As far as cost goes, I did look into ecgs and I love the simplicity as well as the warranty. But I don't have the spare coin to drop 3.5k on my gears right now. So I'm doing the rebuild myself, and it should come in around $600-750 with some quality parts. Yukon gears and a house brand rebuild kit from a parts store. Not the most ideal, but what's realistic for me at the current time.

I agree though 3.73 is small dick energy, I want to go 4.56 because I have plans of a mid or long travel suspension down the road.

 

yes e-locker TRD OR is 8". I've heard it's possible to retrofit an 8.4" carrier into an 8" housing, and that 8.4" is still technically 8" but just called that to differentiate the fact it has a larger carrier while not necessarily being truly 8.4" in size.

IDK why but Revolution Gears has been out of stock for a while on gearset kits. Otherwise they're about $1k.
Unless they're strictly honoring shop sales before general public sales, especially if there is COVID-related limited supply from manufacturing, which is understandable
I hear they are the best brand.
I'm not sure what the packages cost from others like Yukon, ECGS, etc.

 

I would decide on tire size, then base gearing based off that, even if the tires come later
I took out my front drive shaft when it was regeared to make sure no problems would come up and it worked out fine that way

(Currently on 5.29s and 35s, waiting to get 37)

 

So, is 5.29 on a 33 or 35 adequate or even overkill if I don't intend to weigh much at all? I mean would a 4.56 do the job? This is gonna be a daily driver as well as a weekend offroader, so I'm trying to retain some of the drivability.

 

Well Yukon is a bit more affordable with ring and pinion sets coming in at the 250-350 mark. Ecgs is HIGH dollar. I priced out a direct bolt on carrier assembly and it was about 2k. I didn't look at their gear sets alone though so I cant speak to that.

Update:just went and looked at ecgs and they sell Yukon gears and nitro gears. Both at pretty good prices.

 

5.29 is overkill with 35s and armor

For 33s on a lighter truck I’d personally stick with 4.10
For 35s on a light truck I’d go 4.56

 

Where is everyone getting the high price for ECGS? Swap this in and send yours back and you get the core charge back. Add a few options (solid spacer) and you're still under 1k.




I have 35s 316/75/16) with 488s and am happy with them. I agree with others that you should decide on tires and choose gears from that point. I'd also do F&R at the same time so you don't limit yourself to 2WD.

 

When I priced out a carrier assembly it was 1750, but yes half of that was core. It's definitely the route I would go if I had the cash to spend at the moment, but unfortunately I'm gonna have to do this piece meal.

 

They refund the core right back to you once you send in your old ones so quoting that as part of the price on here is confusing and misleading to folks that haven't researched this topic.

Typically you can get both front and rear ECGS diffs for around $1500-1700 total depending on your options. Prices obviously change with addition of locker(s) or Trutrac units.

Buying assembled third members from ECGS vs buying the gears and rebuild kits separately is a very marginal different in price. You're essentially paying an extra couple hundred bucks to have them assembled there and sent out along with having their warranty.

I have price compared this lots of different ways for previous Tacoma's I regeared, and everytime I ended up going with ECGS assmbled diffs because their price couldn't be beat.

 

For those asking what gear ratio is best for a given tire size, a big factor not being mentioned is if you have an auto vs manual transmission.
A stock 2nd gen at 75mph will run ~2600rpm in 6th gear with a MT. The same truck in an auto trans will run 400rpm lower at the same speed.
Using the grimmjeeper calculator helps with figuring out the appropriate gear for you truck and tire combo.
http://www.grimmjeeper.com/gears.html

 

Well, I get a little bit of a discount on parts which makes the cost of a rebuild a bit less expensive. But I agree, if between now and then I suddenly end up with a couple extra thou I will most certainly just order a front and rear from ecgs.

Also, you're right I failed to mention my truck is an automatic. It's got a cool 8 ball shifter knob though!

 

it gets expensive quick if you start adding lockers

 

Which begs the question...can I get one of these and still use my factory e locker? Or am I painted into a corner and forced to purchase a locker upgrade?

 

If you have an oem locker, then that’s what your stuck with. The Harrop and ARB lockers are for the 8.4 diff where the oem E locker is the 8”.

the 8.4 comes in The sprt LSD and the open diff from the factory.

 

4x4 has two diffs. $765 x 2 is $1400 minimum
I priced out used flanges, maybe solid spacer instead of crush sleeve

u saying it’s worth to go 4.10 or 4.56 without lockers for $1400+?
Many people want to go lockers at the same time “may as well while you’re in there”
ARB air locker $1000 x 2 = $2000 + $1400 base gears job = $3400 minimum

if he decides on an ARB air locker
Would ECGS maybe mail him one built into an 8.4” 3rd and accept an 8” elocker as core return?

 

Yeah they probably would accept the core swap, however, to go from an 8” to an 8.4” you would have to swap the rear axle housing as well to accept the 8.4” non ELD third member. The opening on them is shaped differently and IIRC, has less clearance in the 8”