Question Front diff/locker

[Romer]

I have been reading threads on busted front diffs, even the newer ones. Seems the solution is to install a front locker and everyone agrees. What I couldn't clearly get from the threads

Is it the structural integrity the locker adds to the diff making it less prone to breakage. e.g doesn't matter if you engage it, just being there adds strength

or

do you engage it to provide integrity when you get in certain situations. Not talking about engaging to help you wheel or provide more traction.

I just want to understand the failure and solution (locker)

and yes, I am getting a 100 and no Shotts I am not on your side. Just looking for a more comfortable DD for my aging fat behind.

 

[Trunk Monkey]

The 98-99 front diff has 4 spider gears in the carrier. The thought is that under stress there's enough movement there for the pinion to slip on the ring gear teeth and that's what causes damage. The later diff has 6 spiders, so there that much more surface area of gear teeth in contact with each other and less likely to be a problem. The carriers are different part numbers, so it may be that there's a different build or more material that supplements the strength.

However, this is like the 80 series HG. You're in the microcosm of Mud, so it seems that every 98-99 truck has busted a diff, just like every 80 series is a ticking HG time bomb. I know several trucks of those years that have been wheeled hard and are just fine.

The ARB locker replaces the whole carrier with a more solid piece. Just it being there provides the structural integrity in the diff.

Pics:

1- 98-99 2 pinion
2- 00+ 4 pinion
3 - ARB

 

[jonharis]

ARB replaces entire carrier. My understanding is that just having the stronger carrier is the solution. I probably would have done it even if I never intended to actuate it....but what's the fun in that.

 

[Romer]

That helps quite a bit. Now I understand why the front locker is more important than the rear.

Need to do more research on Atrack to see if with a front locker and ATRAC if I need the rear as well

Like an 80, it's a slippery slope, IF you do both lockers then why not regear now rather than later. Doubt I need the gears with the 33's on the truck, but I am use to running 35's. I really only went to 35's in planning for the Rubicon. Everyting I did before that with 33's was just fine.

Maybe just the front locker and play with ATRAC and see how it goes. Never used ATRAC and have been reading a while. I know how it works, but experiancing it and learning how to use it as a tool is a different matter. I always like driving the 80 open to see if I can before I engage a locker, but ther are times they are needed or rather my skill isnt to the point I could go without them 100%.

 

[Trunk Monkey]

ATRAC is very impressive. I think it would suit the moderate wheeler just fine. ATRAC trucks will all have the later diff, so there's a high likelihood you'd never have a problem at all. Unless you have needs for extreme traction, you could probably go with ATRAC alone.

 

[pfran42]

Slippery slope indeed. When my 4 pinion front diff went, the options ranged from $1500-7500 (including PM). The minute you decide that you don't want to have OEM fail on you again, it is a very slick slip n' slide towards the larger figure. Glad I knocked it out though. The Slee rear bumper is gonna be a lot easier to justify to the wife now!

Here are some very good (and probably biased) videos from ARB that explain and compare 3 types of traction control. They use 3 Prados with each equipped differently and demonstrate how each system works and why the air lockers are superior for traction. After watching these, I drank the Kool-Aid...

http://www.youtube.com/watch?v=C2wkW05Pc6c&feature=player_embedded#at=355
http://www.youtube.com/watch?v=YNFacsKnswM&feature=related

Here is a demo with a 100 Series.

http://www.youtube.com/watch?v=Z257wwbPC70&feature=related

 

[1loudLX]

You don't need to do both with atrac, it'll just think both wheels are spinning together and do nothing. HOWEVER!!!! with VSC, you do not want to engage the front or rear lockers before engaging the center diff(which disables vsc).

 

[jonharis]

Just do front/rear ARBs and 4.88s and be done with it. Best mod after sliders IMO.

 

[sleeoffroad]

However, this is like the 80 series HG. You're in the microcosm of Mud, so it seems that every 98-99 truck has busted a diff, just like every 80 series is a ticking HG time bomb. I know several trucks of those years that have been wheeled hard and are just fine.

I agree with you on the HG for the 80, but I advise all my customers to put a front locker in a 100 when you wheel it. We have seen way too many of them break in situations where it should not.

3 - ARB

Just to be clear, that is an old picture of an ARB. The two halves does not bolt together like that anymore.

I think there are different breakages.

1. Spider gears break teeth. I believe that is due to shock loads on the spiders from wheels that wildly spin and then grab traction. Typical that is a toot broken off completely. So here, having an ARB is going to help some due to the materials the ARB is made off, but the way to eliminate that is to have it locked.

2. Stripped teeth on pinion or ring gear or both. There could be a variety of reasons for this. Could be carrier deflection, could be housing deflection, could be loss of preload or a variety of different things. Here the ARB is better than the stock carrier since it is way stronger.

This is what the new lockers look like.

The area where the ring gear bolts to is way thicker and stronger to stop deflection and the carrier does not split at the end cap anymore.

If you are going to add an ARB, use it. How it will work with only a front I do not have experience, but since the front diff is still pretty small, I would like the rear to do most of the work, so I would rather run a ARB in the rear as well.

 

[Nottajeep]

Another 80 guy crosses over... once you get over the lack of a SA up front, you'll never look back.

and yes, I am getting a 100 and no Shotts I am not on your side. Just looking for a more comfortable DD for my aging fat behind.

 

[Romer]

Another 80 guy crosses over... once you get over the lack of a SA up front, you'll never look back.

My oldest daughter has a 4runner with IFS and has kept up with me wherever I have gone. I have never had an issue with IFS. I still love my 80, just want something more comfortable as I grow older

I will give up one of my two 80's so I swill still have an 80, a 4 runner and a 100. The 80 I am selling is already spoken for.

 

[bluecruiser]

Just to be clear, that is an old picture of an ARB. The two halves does not bolt together like that anymore.


when was the new style arb introduced?

thanks