Blew the Front Diff (Broken Ring and Pinion)

[Trunk Monkey]

Usually it's the small spider gears that slip and break and then the chunks from that go through the ring and pinion, breaking those. The design of the carrier, r&p, and the spider gears allows for some deflection under certain circumstances. The deflection occurs much more easily with the 98/99 only having 2 spider gears, not so much with 00+. The "best case" break is that you shear teeth off the spider gears only and the ring and pinion remain undamaged. Then you only have the cost of a new carrier or ARB. If the spider gear parts take the ring and pinion with them, then you get new gears too.

The ARB replaces the whole spider gear assembly with a much beefier unit The ring bolts to the ARB carrier and doesn't allow for the slippage the OEM set up does. Plus, you get a fast acting locker that is a HUGE traction assist and keeps you out of those situations where you're bouncing and slipping.

https://forum.ih8mud.com/showpost.php?p=6797577&postcount=2

 

[rusty_tlc]

..... I'd hate to have it happen to my 99 on the other side of the country; I wouldn't know where to start...

.....

The readers Digest version;
1- Drop the belly pan and remove front drive line.
2- Remove drive flanges in front hubs, keep track of which snap ring goes with which side. I keep a few sandwich bags and a marker in my tool box for stuff like this.
3- Lock center Differential.
4- Drive home, I really don't think there is a limit as to how far you could drive with the truck this way.

It only take a hand full of tools and about half an hour. If you have a stock planetary it might be worth while to get a spare set of drive flanges and have the splines milled out, that way you could close the hubs up and keep any dirt and water from getting in.

 

[paflytyer]

The OEM front diff (regardless of year) flexes under stress, the ARB is a much more robust unit and does not flex as much. When the front end is stressed the ring gear deflects away from the pinion gear, which is why they pop gears. It will take a few bounces, but the force builds and finally the pinion stretches away from the ring gear and they start eating each other.

Nick...that's a good explanation and it makes sense. But, I spoke to an ARB tech just now, and he said that's not the case.

 

[rusty_tlc]

Good points. Although, there is some labor involved in opening the rear and setting the gears up. I don't know if its worth it or not. I didn't notice a huge amount of difference after going to 35s. I do a lot of mountain driving here and it's not something that bothers me that much. I'm a little slower up the hills, but nothing too drastic. But something I will look into.

Around here the going rate for a master install kit and labor is $500. That's if you R&R the third member.

Then you get into the "While we're in there" cost. As long as you have the axles out you might as well replace the bearings and seals right? And how are those rear disk and pads?

 

[rusty_tlc]

Nick...that's a good explanation and it makes sense. But, I spoke to an ARB tech just now, and he said that's not the case.

What was his explanation?

 

[spressomon]

It's the difference between the rigidity of the ARB carrier compared to the OEM carrier...

Play...repeat...play...repeat...play...repeat...play...repeat

 

[tabraha]

I bookmarked Christo's thoughts on this many moons ago...

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.




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.

That was taken out of THIS thread btw if anyone is looking for the context of the post.

 

[OregonLC]

Was talking to some of Carl's guys at the NW Overland rally and they're fans of the TJM over the ARB. A few $ less and a better design (according to them). I guess the TJM has avoided the pressurized housing that the ARB has. Give Just Differentials a call...

 

[Letsgomoreplaces]

Front diff

The front diffs are a fairly common failure on the 100 series. The OEM setup often times is lacking in much carrier bearing preload and coupled with a weaker cast carrier they tend to deflect considerably under load which leads to failure. Atrac doesnt work in its favor. Another common time for failure with an open diff when the tire is spinning in the air and then comes in contact with traction. The Locker helps in many ways.
-Stronger more rigid case allows for much less deflection
-Internals are considerably stronger. 2 pinion OE diffs fail here often, 4 pinion diffs also fail here.
-When locked, the locker will split the tourque side to side as well as eliminate uncontrolled wheelspin.
-Requires setup, so allows the opportunity to do a fresh setup and replace worn bearings and tighten the carrier bearing preload, install a solid spacer etc. All contribute to less deflection.

A big portion of the cost to do Lockers or gears is in fact Labor. You were likely on borrowed time, so no I'd just look at it as getting all the use you could have out of the old setup, and now time for an "upgrade", which isnt that much more of a cost than a "repair". Upgrades are way more fun to spend money on

As for having this done, try Slee offroad if you are in the denver area

Someone is going to have to explain how a locker will strengthen the ring and pinion and prevent this from happening again?

The particular spot that I broke on the trail wouldn't be someplace I would have locked the front anyway. How does the ARB or TJM make the ring and pinion stronger? It seems like that's what's failing on most of our 100s.

EDIT: just got a good explanation. The answer is that it won't. Just lock it up and avoid taking the chance of one wheel spinning when it shouldn't.

 

[OregonLC]

Then you get into the "While we're in there" cost. As long as you have the axles out you might as well replace the bearings and seals?

Probably no necessary unless there is a specific issue/need. Don't recall any going south with normal trail use. Not much bang for that buck.

 

[PIPO]

Do aftermarket lockers require more maintenance/service than OEM types?

 

[paflytyer]

It's the difference between the rigidity of the ARB carrier compared to the OEM carrier...

Play...repeat...play...repeat...play...repeat...play...repeat

Dan if this is directed at my asking questions, than I apologize. This is new territory for me and I'm learning on the fly. Nothing motivates learning like spending money.

I have a lot going on right now and searching MUD for hours isn't something I have time for. I spoke with a tech from ARB and it appears he wasn't totally up to speed on the OEM diff carrier for our vehicles. I have contributed to helping others in the past and I think I've earned the right to ask a question, even if it's been covered before. Weaker OEM carrier allows more deflection, coupled with tolerances that are greater than when brand new, equals a weak link. I *think* I'm getting up to speed. I spoke with Carl and Christo for a while this afternoon.

 

[yeti in ga]

When mine breaks pulling into the walmart parking lot , I am going ARB all the way. But really I am glad I have not had a break yet...... with all the talk about the weak front 99. I think its more about the 35 inch tires and a matter of time. Sorry to hear about your unexpected maintenance. will follow your fix..

 

[spressomon]

Dan if this is directed at my asking questions, than I apologize. This is new territory for me and I'm learning on the fly. Nothing motivates learning like spending money.

I have a lot going on right now and searching MUD for hours isn't something I have time for. I spoke with a tech from ARB and it appears he wasn't totally up to speed on the OEM diff carrier for our vehicles. I have contributed to helping others in the past and I think I've earned the right to ask a question, even if it's been covered before. Weaker OEM carrier allows more deflection, coupled with tolerances that are greater than when brand new, equals a weak link. I *think* I'm getting up to speed. I spoke with Carl and Christo for a while this afternoon.

Not personal. Not too far off in the not so distant past the peanut gallery took a staunch anecdotal position only 2-pinion diffs, i.e. '98-'99, were the problem child.

If its been said once its been said a hundred times...when folks ask 'what should be their first 100-Series mod'...the front diff is it regardless of year. Just trying to save the newbs some chinga or worse.

Yeah...somedays I can be an arsehat...today was one of those days alright

 

[spressomon]

Do aftermarket lockers require more maintenance/service than OEM types?

Yes and no

Can't speak for TJM as their the new-ish kid on the locker block at least in North America but the newer ARB design has proven reliable AFAIK. FWIW: My ARB front locker was purchased in '06 and its not given me any trouble.

But...the ARB air locker locks and releases significantly quicker than my rear OEM e-locker; not quite apples to apples compare due to front versus rear designs on OEM (80-Series...since 100's never got a front OEM locker).

 

[rusty_tlc]

Probably no necessary unless there is a specific issue/need. Don't recall any going south with normal trail use. Not much bang for that buck.

Labor is always the major cost, either in time or money. Skipping something like seals and bearings while you have the axle apart makes no sense at all.

Do aftermarket lockers require more maintenance/service than OEM types?

I've had ARB lockers in my FJ40 for 15 years. Over time the lines will get brittle and need to be replaced, I check mine every year sometime more often. About 7 years in there was an internal o-ring that needed to be replaced in one, the other one lasted 9. My pump has been re-built three times and is finally worn out, old design, I think the newer models they sell could last a lot longer, the rebuild parts are cheap and the process is easy.

You will want to get a few feet of spare air line and a couple of quick splices, ARB USA has all that stuff at very reasonable prices.

I cannot say enough good things about the quality of customer service I have received from ARB USA over the years.

 

[AimCOtaco]

Labor is always the major cost, either in time or money. Skipping something like seals and bearings while you have the axle apart makes no sense at all.

It's not that common to change the carrier main bearings because they seem to last almost forever and they are big money.

The Input and Output seals should be changed. The pinion bearings should probably be changed, and in most cases a solid crush sleeve is installed as well.

I'm also a strong believer that the better re-builders builds will outlast the factory because they tend to use a higher carrier bearing pre-load which reduces R-P deflection which causes breakage. I think this holds true no mater which carrier is used, 2, 4, or aftermarket locker. When it comes to diffs, the best parts in the world won't get you down to the corner store unless they are set up correctly or even better, set up painstakingly by a picky pro.

 

[paflytyer]

It's not that common to change the carrier main bearings because they seem to last almost forever and they are big money.

The Input and Output seals should be changed. The pinion bearings should probably be changed, and in most cases a solid crush sleeve is installed as well.

I'm also a strong believer that the better re-builders builds will outlast the factory because they tend to use a higher carrier bearing pre-load which reduces R-P deflection which causes breakage. I think this holds true no mater which carrier is used, 2, 4, or aftermarket locker. When it comes to diffs, the best parts in the world won't get you down to the corner store unless they are set up correctly or even better, set up painstakingly by a picky pro.

All part of the learning process for me.

I'm *hoping* to be back on the road and ready to go for 100s in the Hills. Time isn't on my side and I already had a full plate before this. Christo Slee from Slee Offroad and Carl Montoya from Just Differentials are working hard to get me all the parts I need to get going again. They are also working with a full plate of other things going on. There isn't two better people to go to when it comes to the 100 Series or differentials.

I'll continue to update as I go through getting torn down and back together.

 

[AimCOtaco]

All part of the learning process for me.

I'm *hoping* to be back on the road and ready to go for 100s in the Hills. Time isn't on my side and I already had a full plate before this. Christo Slee from Slee Offroad and Carl Montoya from Just Differentials are working hard to get me all the parts I need to get going again. They are also working with a full plate of other things going on. There isn't two better people to go to when it comes to the 100 Series or differentials.

I'll continue to update as I go through getting torn down and back together.

Well damnit, quit typing and tear that sucker down! If you do have to ride along for Ouray at least you won't have to worry about breakage or fuel

 

[rusty_tlc]

It's not that common to change the carrier main bearings because they seem to last almost forever and they are big money.

The Input and Output seals should be changed. The pinion bearings should probably be changed, and in most cases a solid crush sleeve is installed as well.

I'm also a strong believer that the better re-builders builds will outlast the factory because they tend to use a higher carrier bearing pre-load which reduces R-P deflection which causes breakage. I think this holds true no mater which carrier is used, 2, 4, or aftermarket locker. When it comes to diffs, the best parts in the world won't get you down to the corner store unless they are set up correctly or even better, set up painstakingly by a picky pro.

I was talking about the axle seals and bearings. IMHO it would be silly not to attend to them while you have the axle apart.

IIRC the master install kit for the diff is about $200 which includes all the bearings and seals for the diff, am I mistaken?

When you say solid crush sleeve do you mean a machined sleeve?