4th Gen Front & Rear Differential Question

[MarkinWMich]

I understand that I have, in the transfer case, a Torsen LSD differential "with locking feature".

There is a differential in the front and rear axle housings, as well. I am unable to find specifically what type of factory differentials the front and rear have.

Any technical data (spline counts, etc.) would be helpful, as well.

I am looking to do a re-gear (4.56 or 4.88) with possible differential swap, as well...$$$ permitting. I would like to know a little bit more about what I have so I can track down the correct parts and how much they cost.

Door Plate Data:
GRN215L
GKAGKA
A01A A750F

Transfer Gear: VF4AM

VIN: JTEBU14RX********

 

[lehiguy]

The front is a "clam shell" 8" reverse rotation gear set. Nitro Gear has some ratio options and ARB makes an air locker for it. The rear is super ubiquitous Toyota 8" which happens to be a 30-spline. You can get virtually any ratio and any type of traction device for the rear. I went with the Toyota E-locker and 4.10 gears for my 285/75 tires.

 

[Bskelton]

Check out East Coast Gear Supply. You can get complete diffs with whatever ratio and locker options you want. They also have great customer service and will answer any questions you have. I used them for my diffs and am glad I did.

 

[t-man]

The front is a "clam shell" 8" reverse rotation gear set. Nitro Gear has some ratio options and ARB makes an air locker for it. The rear is super ubiquitous Toyota 8" which happens to be a 30-spline. You can get virtually any ratio and any type of traction device for the rear. I went with the Toyota E-locker and 4.10 gears for my 285/75 tires.

Is it the same rear end with the V8? Everytime I look around they all say V6 rear diff...

 

[superman3043]

Is it the same rear end with the V8? Everytime I look around they all say V6 rear diff...

Yes, same thing. The 8" rear in ours are referred to as the "V6" or "Turbo" as opposed to the "4 cylinder" or "high pinion" variants of the Toyota 8". It's just a naming convention they assigned to the Diff doesn't really have anything to do with which engine is in your truck. The front is an 8" IFS clamshell.

29 Spline for 2001 and newer, 27 spine for older than 01'.

 

[t-man]

Yes, same thing. The 8" rear in ours are referred to as the "V6" or "Turbo" as opposed to the "4 cylinder" or "high pinion" variants of the Toyota 8". It's just a naming convention they assigned to the Diff doesn't really have anything to do with which engine is in your truck. The front is an 8" IFS clamshell.

29 Spline for 2001 and newer, 27 spine for older than 01'.

Knew I should've just asked you! Lol, you always have the answers I need. So we have 28 spline not 30?

 

[KidVermicious]

Is it the same rear end with the V8? Everytime I look around they all say V6 rear diff...

They say "V6 rear diff" because some early 4Runners got what is now called the "4cyl" diff, and some got what is now called the "V6" diff (even though it first appeared in turbo-equipped 4cyl models). In reality, there's no such thing, because some 4cyl trucks and 4Runners got two pinion thirds and carriers and "V6" ring and pinion. It's a cluster, be glad you don't have to figure it out - for you, an 8" axle is an 8" axle and all your thirds and carriers and bearing sizes are the same (and swappable), and they're all the same "V6" carrier/third ever since the second gen 4Runner in 1990.

That's not the case for the Tacoma, by the way. They do have differences in the axle depending on model, so if you're looking to regear with a used Taco diff do your homework first. But all 4th gen 4runners have the same rear axle and third.

 

[MarkinWMich]

Summary:

Rear End Housing: "Turbo/V6" 8-inch
Front End Housing: IFS Clamshell 8-inch

Front Ring and Pinion: Reverse Gear (29 or 30 spline?)
Rear Ring and Pinion: (29 or 30 spline?)

Differentials: (29 or 30 spline?)

Axles: (29 or 30 spline?)

Sorry, receiving some confusing information regarding spline counts...at least to me.

 

[superman3043]

My info on the spline count came straight from ECGS. You can double check with Chase there, but I'm gonna stick with that.

It's what they call "big pinion" or something like that.

 

[t-man]

They say "V6 rear diff" because some early 4Runners got what is now called the "4cyl" diff, and some got what is now called the "V6" diff (even though it first appeared in turbo-equipped 4cyl models). In reality, there's no such thing, because some 4cyl trucks and 4Runners got two pinion thirds and carriers and "V6" ring and pinion. It's a cluster, be glad you don't have to figure it out - for you, an 8" axle is an 8" axle and all your thirds and carriers and bearing sizes are the same (and swappable), and they're all the same "V6" carrier/third ever since the second gen 4Runner in 1990.

That's not the case for the Tacoma, by the way. They do have differences in the axle depending on model, so if you're looking to regear with a used Taco diff do your homework first. But all 4th gen 4runners have the same rear axle and third.

Awesome! Now THAT should be a sticky!

 

[lehiguy]

Awesome! Now THAT should be a sticky!

V6 appellation is from a time when a V6 was a new development (1988), and it was the carrier, not the gears that were different. Spline count usually has reference to the axle spline, but there are now two different pinion flange spline counts. After market gear sets all utilize the old 27-spline flange, so you will need to get a flange that is 27-spline but has the big bolt pattern to match your Runner. FJ60 Land Cruisers after 1985 use a flange that works... I think. They looked identical but I never got the chance to test my theory. Just to keep things interesting, there was also a factory 4.88 gear set with a proprietary carrier that was different from all the rest. Patience can pay big dividends. I scored a 4.10 ratio Elocker on Ebay that shipped right to my door for $125. It needed nothing but my pinion flange to work. 4.56 gears were common in third gen Runners with the larger tires. A trip to the wrecking yard would likely yield one, but only for the rear; the fronts are different.

 

[BlackWorksInc]

I believe the V8 & V6 front differentials are slightly different in size due to the ADD on the V6, I don't remember the exact differences, but I believe the V8's is a hair bigger.

 

[Bskelton]

I believe the V8 & V6 front differentials are slightly different in size due to the ADD on the V6, I don't remember the exact differences, but I believe the V8's is a hair bigger.

I'm pretty certain that the front differential itself isn't any different V6 or V8. I think the only diffence is in the ADD tube.

 

[Jeremy556]

I'm pretty certain that the front differential itself isn't any different V6 or V8. I think the only diffence is in the ADD tube.

Yep, diff is exactly the same, just whether or not it has an ADD on the tube that bolts to the right side.

 

[MarkinWMich]

Are the stock differentials a limited-slip, positraction, or something else?

What combinations of differentials are desired? For example, air or e lockers front and rear, or something else?

 

[superman3043]

Are the stock differentials a limited-slip, positraction, or something else?

What combinations of differentials are desired? For example, air or e lockers front and rear, or something else?

Stock diffs are open unless you have the ultra rare 2009 Trail Edition, in which case comes equipped with an e-locker. Only factory traction aids are ATRAC which is managed with sensors and computer braking, not within the diff, and the center torsion diff lock. Actually some may come with limited slip... 2WD maybe?

Desired combinations? I guess there are advantages and disadvantages to everything.

Mechanical lockers are cheaper and operate without intervention, but they might not be as steetable as a selectable locker.

Selectables (electric & air) are nice in that they give you full control between open and locked, so they're very streetable, but require user input, and are expensive.

Between the two, air lockers also require an OBA system. Added cost, but could be a good thing if you desire OBA. Also issues can be inherent with these types system, like leaks and oil intrusion and stuff like that. More stuff to go wrong basically.

E-lockers don't really have an off the shelf plug & play solution except for those Aussie made ones that popped up recently that nobody owns. Some options are to source a Toyota locker and retrofit it which requires a good amount of work. You could possibly also find a complete axle with e-locker say from an FJC or something.

 

[MarkinWMich]

I did some additional searching. Around here in Michigan, there really are not that many off road trails or parks, but what is available is typically made up of "soft stuff" like sand and mud. Winter driving is also a mix of snow and ice.

What I am reading is that an open diff is preferred over a LSD for this application. From what I understand, the open diff engages "softer" instead of "grabbing" which is important if you want to maintain control on slick roads.

However, if you are tracking through or are stuck in deep snow or mud, a locker is desired. So, as expensive as they are, something like an ARB air-locker might be the ticket.

Any other thoughts?

 

[CAN-03runner]

I did some additional searching. Around here in Michigan, there really are not that many off road trails or parks, but what is available is typically made up of "soft stuff" like sand and mud. Winter driving is also a mix of snow and ice.

What I am reading is that an open diff is preferred over a LSD for this application. From what I understand, the open diff engages "softer" instead of "grabbing" which is important if you want to maintain control on slick roads.

However, if you are tracking through or are stuck in deep snow or mud, a locker is desired. So, as expensive as they are, something like an ARB air-locker might be the ticket.

Any other thoughts?

If you think the trails are muddy enough that with Mud tires, 4x4 and Atrac you'd still get stuck, or loose traction, a winch might be what you need. If no traction is to be had, the locker won't help either.

I Hate MUD but I LUVmyWinch

 

[superman3043]

from experience, my rear locker in the snow is absolutely terrible. Open diff is much better.

 

[aha2988]

Axles front and rear are 30 spline shafts and the rear pinion is 30 spline from the factory on all the 4th gens. If you regear however, you will be swapping to a 27 spline pinion flange to carrier the aftermarket gears. I found this info here: http://home.4x4wire.com/erik/diffs/#taco_ifs

Ninja Edit: This is controversial to what Pd found on ECGS's website but I will say it doesn't really matter what spline count you have currently if your regearing you just match the pinion flange spline count with the pinion of your choice. The carrier will remain a 30 spine to match your axle shafts.

and I'm never wheeling with you again superman if you say that you prefer open diffs than lockers :guitar3: haha


For the OP: https://www.youtube.com/watch?v=K4JhruinbWc A good video to show you how the differential operates and how locking the left and right axles shafts together effect everything.

https://www.youtube.com/watch?v=bvOgneVbVnE

https://www.youtube.com/watch?v=8M_Vzn7Ugs4

some other videos to show when a locker is necessary.

Times when a locker will mess you up is when you have both wheels on an axle spinning in loose material the traction holding the axle tracking in a straight line is lost so fish tailing or sliding left and right becomes more possible. With a front locker on a hill climb the front or nose of the vehicle can slide to the left or right putting the vehicle perpendicular to the grade causing a roll over situation, where if the front axle wasn't locked you would have one tire that simply holds the vehicle tracking in a straight line and another tire driving the vehicle forward. Lockers will help you in sticky situations and they will also give you the ability to get in even more sticky situations. Knowing how and when to use them is worth noting. When your in mud with vehicle weight resting on all tires lockers help a ton because its all about wheel speed and the more tires you have pulling the more chance you have getting through, on ice climbing a hill lockers can cause you to slide left or right instead of going forward.