Broken Differential Data

[paflytyer]

I'm trying to compile some data/statistics on the infamous broken front ends on the 100 Series. Some of the info will be used for a published article. I understand this isn't scientific data per se, but it can help illustrate a weak point of our vehicle. All I'm looking for is some very basic info for now. This will also serve as a good source of info to see what the most common break is and if there is any correlation between model years. I will start with my info so you get a better idea of what I'm looking for. Unfortunately I'm up against a deadline so I'd like to get whatever I can ASAP. Some of you I speak to on a regular basis and I know your info, but please add it anyway so we get a nice list.

My info.....

2004 LC
120k
35's/22psi
Wheel lift climbing a rocky hill, then traction obtained on large rock.
Broken teeth on ring gear in 3 spots. No damage to spider gears. Still able to drive with small clunk/clunk.
Isolated front and drove home in 2wd.

 

[BackToTheBog]

I've engaged the front diff many times in manifold situations (mud, snow, water) and never had a problem or even strange sounds ('98, 212k, no documented front diff work). I've had ripped front axle boots and dragged on the skid plate/running boards and haven't had issues. All front seals are holding up well. No problems here up front in 4-lo or 4-hi (yet). I've had more problems with the rear (popped seals).

 

[Skidoo]

Pretty sure you have seen my post and video here of how I broke front ring gear at Cruise Moab this year. Think post covers most of the details and has photo of ring gear, but if you need more shoot me some questions. I have put about 50K on truck since I bought and modified it, so a lot of offroad. Feel it was my driving as had done equally tough routes without issues, just wasn't as careful on this one.
Video
The MUD 100 series Videos thread

 

[MtnAddict]

2002 LC
115k
33's/25psi
The dreaded REVERSE while sliding too fast on icy trail.
Ring gear? Spider gears? Still able to drive with clunk, although got worse before we pulled the flanges and front drive shaft.
Will add more as progress is made on it.

 

[bluecruiser]

1999 Series 100
Approx. 130K miles, 33's with about 20psi
Occurred in January 2008
Tried one too many times to climb a ledge. A little too much hopping with the front tires.
Do not recall actual damage. IIRC, both the ring and pinion were shredded pretty nicely. Replaced with brand new front diff and ARB. Cheaper at the time than finding replacement stock R&P.

Link to the rebuild by Zuk.

http://gearinstalls.com/chrishunt.htm

 

[3D FJ]

2003 LX470
81K miles
33's/ 22psi
mild rocky hill climb, CDL locked, left foot braking utilized, not much hopping
Broken teeth on ring gear 2-3 spots, not sure about pinion gear (in garage), no other damage, could not be driven without pulling drive shaft and disconnecting flanges.

 

[uzj100]

7 to 8 years ago while 4 wheeling with a bunch of rovers.
1999 model
Broken while climbing a steep incline. Lifted a front wheel.
This 99 had no rear diff lock.
Drove it to Toyota and said the front end was making funny noises. They replaced it all under the powertrain warranty, no questions asked.
The truck had 285s, lift, front bumper and was covered in mud when I pulled into the dealership.
Had 65k miles on it.

 

[AimCOtaco]

Bump for data.

 

[Shadow]

2003 HDJ100
160,000 km
33's/24psi
Centre diff locked, steep muddy and rutted section of track, Drivers side wheel lifted, tyre came back down and BANG
8 teeth broken on crownwheel in 1 spot. Couldnt get to the brake fast enough when i felt the wheel lift

Couldnt drive it, it would bind up and stop moving forward, Removed front driveshaft and front drive flanges, drove home with centre diff locked.

 

[paflytyer]

The theme so far is wheel lift. The by-product of IFS and its lack of travel.

 

[SanDiegoCruiser]

Has anyone had their diff explode when the rear has been rocked?

 

[bluecruiser]

My rear axle was locked when front failed.

 

[B-RAD]

This is gnawing in the back of my mind for a year now, while on the Rising Sun Spooky Night run last year, Farmham made comment that the front dif should be replaced with a locker and should be at the top of my list of "next improvements" to my 100 series. I have 207K miles on mine, have wheeled it off and on, but not as hard as a lot of you guys, but plan on more in the future and don't want to be $crewed when I do. What's the consensus...bite the preventative bullet, get the front locker and compressor and don't look back...before the bumpers, winch, snorkel and radios(HAM and CB) I want? Sorry to hi-jack the thread, but thought it might be relevent Stan!

 

[Shadow]

It will cost you about the same amount of money to fix your blown diff, as it would to put a locker in.

Only after you fix the blown diff you still don't have a locker

Also, a locker, if its not engaged, will not help prevent the damage to your crownwheel. So you also must remember to use your locker in these situations to prevent the damage.

 

[paflytyer]

It will cost you about the same amount of money to fix your blown diff, as it would to put a locker in.

Only after you fix the blown diff you still don't have a locker

Also, a locker, if its not engaged, will not help prevent the damage to your crownwheel. So you also must remember to use your locker in these situations to prevent the damage.

This is not true. I don't want to turn this thread in a different direction because I really want to compile this data. However, the OEM carrier (what you guys call the crownwheel) that the ring gear bolts to, can and will flex causing the pinion gear to "jump" and break/shear teeth. The carrier on the ARB or TJM is stronger and wont allow for nearly as much flexing or deflection.

 

[Shadow]

That's true to an extent, and certainly for the earlier carriers which only had 2 spider gears, and two very large voids in the carrier, but the later carriers, post 2002, have 4 spider gears and the case is fully enclosed, just like the arb and tjm carriers.

Heres the exploded view of a pre 2002 IFS diff, Note the 2 spider gears and the drawing showing two very large voids in the carrier.
http://www.toyodiy.com/parts/p_G_2000_TOYOTA_LAND+CRUISER_UZJ100L-GNPEKV_4301.html

Heres the exploded view of a post 2002 IFS didd, note the 4 spider gears and cross shaft. The drawing of the carrier in this diagram still looks like the earlier case with two large voids, but the drawing is wrong, the case is almost fully enclosed much like the TJM and ARB lockers.
http://www.toyodiy.com/parts/p_G_2004_TOYOTA_LAND+CRUISER_UZJ100L-GNAEKV_4301.html


This is a photo of my diff, a 2003. Notice the case is mostly enclosed, just a couple inspection and oil holes.

Maybe the ARB and TJM carriers are stronger than the full case toyota carrier, but i think the real protection comes from having the locker locked.


Its still just a little 8" centre, and with heavy 33" or 35" tyres spun up at double speed when a wheel lifts off the ground, then biting back down, its a massive amount of energy transmitted straight to the ring gear and it just doesn't have the ability to absorb it.

The benefit of having a locker in the front end, is when it is locked, there is only minimal energy release when a wheel gets air and regains traction since the other wheel must already be turning.

 

[paflytyer]

This isn't the thread for that discussion. Although, I agree with everything you said except for the 2 pinion vs 4 pinion. There are a handful of us in this thread alone who broke the 4 pinion type.

Here is the thread of my break. Looks the same as yours.
https://forum.ih8mud.com/100-series-cruisers/754865-blew-front-diff-broken-ring-pinion.html

There is some good info from very knowledgable folks.

 

[AimCOtaco]

I sure expected a lot more data on broken fronts, this can't be all of them....

 

[Muddy Bean]

Just blew mine this past Sunday with center and rear locker engaged. Was stuck in snow. Drivers front tire spun down to the dirt and grabbed as I was attempting to rock back and forth out. Haven't done the teardown yet but seems I damaged the spider gears and not the ring/pinion. Won't know for sure until teardown. Btw, this happened in the driveway :-/
1998 LC 142,000 miles

 

[SanDiegoCruiser]

Broke mine in Death Valley heading up to the defense mine. I've done much more technical stuff in the past. 99 with 110K miles. I have since replaced with an ARB & regeared to 4.88.