Ultimate 100 Differentials (1 Viewer)

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I am trying to get this all straight, so that I get the work done I want, and I'd like it documented here for other 100 owners so they can do the same later. No un-necessary commentary, no debating anything else. This thread is just about doing the ARB/gears for the front and rear differentials for the 100 series with 4.88 gears.

Who I want to hear from on this thread:

Slee Off Road

ATS4x4.COM

JT Ring & Pinion

All I want is facts, no debating, no dragging anyone's vehicle in for comparison... Just the facts on what needs to be done to a 100 for 4.88 gears, and ARB air lockers to strengthen the diffs up to handle 35" mud tires.

First, I heard Darren mention this in another thread:

We have been doing this mod for years (ARB), including the solid pinion spacer mod, and with well over 300 + in the field most broken before they came to us, we havent had one back broken, though we have had 3 back with broken cv's.

We do the same mods on the rear diff too.

I take it that there is a machined spacer to be installed etc on this ARB modification for strength. I am trying to remember what it replaces that is normally OEM.......
 
I am trying to get this all straight, so that I get the work done I want, and I'd like it documented here for other 100 owners so they can do the same later. No un-necessary commentary, no debating anything else. This thread is just about doing the ARB/gears for the front and rear differentials for the 100 series with 4.88 gears.

Who I want to hear from on this thread:

Slee Off Road

ATS4x4.COM

JT Ring & Pinion

All I want is facts, no debating, no dragging anyone's vehicle in for comparison... Just the facts on what needs to be done to a 100 for 4.88 gears, and ARB air lockers to strengthen the diffs up to handle 35" mud tires.

First, I heard Darren mention this in another thread:



I take it that there is a machined spacer to be installed etc on this ARB modification for strength. I am trying to remember what it replaces that is normally OEM.......


The machined pinion spacer replaces the OEM pinion crush sleeve spacer.
 
The machined pinion spacer replaces the OEM pinion crush sleeve spacer.


Spresso, you're not on the list of approved posters for this thread, sorry.... :rolleyes:


ooops, neither am I, apparently.... :D
 
Spresso, you're not on the list of approved posters for this thread, sorry.... :rolleyes:


ooops, neither am I, apparently.... :D


Yeah I know but...
 
Ok so what we have so far is....

4.88 gearsets, ARB air lockers with Solid, machined pinion gear spacers instead of the stock OEM crush sleeves.
 
More light received from a PM.....

Checking the Run Out of the ARB Carrier:

The reason you want to have them check the run-out on the ARB carrier: Apparently the ARB carriers can be as much as .030" out! You want the carrier to be essentially flat (or limited run out) so that after you bolt the ring gear to it you are not mating two non-flat surfaces.

This would essentially create a stress riser of sorts...either tweaking the ring gear, the carrier or both... it all makes perfect sense from a machinist/mechanical perspective to have each mating surface flat and within 5-10 thousandths of each other.

This is Darren's (ats4x4.com) contention and per him he has not had any failures since adopting this attention to detail...and I can guarantee you there are alot more 100 users over there that abuse their rigs than anyone here stateside: Myself included.
 
Snook, River City did both Spresso differentials and my differentials with solid pinion spacers. Did you specify you wanted the OEM crush sleeves?
 
Right, the correct thing to do is replace the OEM crush sleeves with Solid Pinion Spacers. We want to keep that clear for future Cruiser owners who want to upgrade their stock differentials.
 
A lot of people get hung up on this. I have posted in the past, the only thing that a solid spacer could help for is that the pinion does not loose preload. I have not seen a single broken diff on a 100 that lost it's preload on the pinion. I would not get hung up on that. The solid spacer does make it easier to replace the pinion seal if it starts leaking, which is also very rare on the 100.

More diffs on the 100 break due to ring gear defection and shock load. The pinion spacer is not going to do anything for this. If the crush sleeve is used right and installed in the correct way, then it is fine.
 
agreed!!!!

Agreed! Yes a solid spacer will help as far as if you need to change a seal or flange later without a full tear down to replace the crush sleeve. It also cannot collapse. However, in the past decade of being in the diff industry and having overseen about 20,000 diff setups I have never seen a crush sleeve cause a failure, long as it was setup properly.
That said the spacers are inexpensive and do provide some benifit, so we generally use them. Not something to get hung up on, and not something that is going to be a night and day difference in strength.
Most failures are due to improper setup, or deflection of the carrier and/or housing, allowing the ring gear to deflect from the pinion and shear the teeth. A good amount of carrier bearing preload is one thing you can do here to prevent deflection. Also the arb case is much stonger and more rigid, thus preventing deflection.
As far as checking the carrier runout. I dont know why people are so into mentioning this. This is just a normal step? Any diff should be checked for runout. That is like saying you can make a super landcruiser diff by checking the backlash. Its just a normal procedure.


A lot of people get hung up on this. I have posted in the past, the only thing that a solid spacer could help for is that the pinion does not loose preload. I have not seen a single broken diff on a 100 that lost it's preload on the pinion. I would not get hung up on that. The solid spacer does make it easier to replace the pinion seal if it starts leaking, which is also very rare on the 100.

More diffs on the 100 break due to ring gear defection and shock load. The pinion spacer is not going to do anything for this. If the crush sleeve is used right and installed in the correct way, then it is fine.
 
Agreed! Yes a solid spacer will help as far as if you need to change a seal or flange later without a full tear down to replace the crush sleeve. It also cannot collapse. However, in the past decade of being in the diff industry and having overseen about 20,000 diff setups I have never seen a crush sleeve cause a failure, long as it was setup properly.
That said the spacers are inexpensive and do provide some benifit, so we generally use them. Not something to get hung up on, and not something that is going to be a night and day difference in strength.
Most failures are due to improper setup, or deflection of the carrier and/or housing, allowing the ring gear to deflect from the pinion and shear the teeth. A good amount of carrier bearing preload is one thing you can do here to prevent deflection. Also the arb case is much stonger and more rigid, thus preventing deflection.
As far as checking the carrier runout. I dont know why people are so into mentioning this. This is just a normal step? Any diff should be checked for runout. That is like saying you can make a super landcruiser diff by checking the backlash. Its just a normal procedure.


Carl,
Darren once stated he sees ARB carriers as much as .030+" out or such measurement...that's where this came from originally. If the carrier is that much out it only makes sense to me, from a machinist perspective, to have two mating rigid surfaces be as close to flat as possible/reasonable.
 
My regeared 4.88 truck /w stock OEM crush sleeves on 35" MTR performed solid after went thru Deer Valley Trail and Slick Rock Road AFTER the front diff exploded twice.

Cheers,

And I have OEM sleeves because when I did mine nobody knew about anything better.
 
Carl,
Darren once stated he sees ARB carriers as much as .030+" out or such measurement...that's where this came from originally. If the carrier is that much out it only makes sense to me, from a machinist perspective, to have two mating rigid surfaces be as close to flat as possible/reasonable.

Consider the source? :D:hillbilly:
 
Consider the source? :D:hillbilly:


Regardless of what you think of the source I still would not be OK with mating parts like carriers and ring gears if the mating surfaces were not flat.
 
I just replaced my blown up diff on my '99 100. I did not regear but I did add the ARB. I had the solid spacer used to replace the crush sleeve. Not because I knew any better, but I just liked the bling;)

I should have a complete write up soon that is being done by the guy who did my ARB install. His website is www.gearinstalls.com This guy is really into diffs. I will post up when he gets done with my link, which he said may be done tonight...
 
I agree, you dont want runout. I dont know why people are so into mentioning this. This is just a NORMAL PROCEDURE. All differentials need to be checked for runout.


Carl,
Darren once stated he sees ARB carriers as much as .030+" out or such measurement...that's where this came from originally. If the carrier is that much out it only makes sense to me, from a machinist perspective, to have two mating rigid surfaces be as close to flat as possible/reasonable.
 
I agree, you dont want runout. I dont know why people are so into mentioning this. This is just a NORMAL PROCEDURE. All differentials need to be checked for runout.


Carl: Why wouldn't you want to know if the ARB carrier is completely flat...before you bolt the ring gear to it? I take, from your comment, you assume the ARB carriers are machined and/or manufactured to a tight tolerance?
 
runout

I would say that ARB units are straight much more often than not. Still, they need to be checked, just like any diff. Also backlash must be checked, also pinion preload, pinion depth, etc. They are all important.



Carl: Why wouldn't you want to know if the ARB carrier is completely flat...before you bolt the ring gear to it? I take, from your comment, you assume the ARB carriers are machined and/or manufactured to a tight tolerance?
 

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