100 Series Front Diff Failure - Random Chat (4 Viewers)

[cruiseroutfit]

There are two basic failure modes on the front IFS 100 diff, R&P or spider-gears. The earlier 2-pinion diff is well know to fail at the spiders/cross-shaft but they don't always fail that way, on occasion they too break a ring/pinon. I'm curious what year and what failures you've personally encountered.

This is out of a customers 1999.

Fortunately we had a core front assembly to swap him out in a hurry, he went ARB at the same time. This core will now make a great 4.88/ARB setup... or we have stock front carriers we can use to build anything else too

 

[dinnertime]

I've got a 4 opinion that something broke loose and damaged the ring gear. Not catastrophic failure, but so much debris the whole thing had to be replaced. I'll try and snap some pics this weekend, its sitting on my work bench.

 

[cruiseroutfit]

I'd be curious what the actual failure mode is

 

[dinnertime]

I'd be curious what the actual failure mode is

If I get time, I'll strip it down and find out.

 

[Spike555]

What causes these failures? In my experience diffs only fail if abused, ran low on fluid, worked to hard, to much touqre, so is there a general consensus as why these fail?
Just bad luck? Bad design? Abuse? Neglect?
I'm curious.

 

[EarthX]

2002 LX470.
Ring and pinion failure...broke in my driveway. Snow on the ground and I little wheel spin.‍
Happened to be Christmas morning too.

 

[lt1fire]

you going to make a 9.5 inch front diff for us Kurt???


only half joking


actually not joking at all



just take my money

 

[cruiseroutfit]

What causes these failures? In my experience diffs only fail if abused, ran low on fluid, worked to hard, to much touqre, so is there a general consensus as why these fail?
Just bad luck? Bad design? Abuse? Neglect?
I'm curious.

Wheel spin and sudden traction seem to be the major culprit. On that note I've seen less R&P on locked axles whereas you would think you'd see more as they are being pushed harder. That dynamic shock load of a spinning tire suddenly grabbing traction just doesn't make them happy

 

[cruiseroutfit]

you going to make a 9.5 inch front diff for us Kurt???


only half joking


actually not joking at all



just take my money

That is an interesting idea. The low pinion would be an issue. I wonder if a 200 diff would have some legs? We've (Canguro Racing) flogged our 200 pretty hard with 37's and had overall good luck with the front diff. We've broke a set or two of gears but it gets hammered.

 

[lt1fire]

That is an interesting idea. The low pinion would be an issue. I wonder if a 200 diff would have some legs? We've (Canguro Racing) flogged our 200 pretty hard with 37's and had overall good luck with the front diff. We've broke a set or two of gears but it gets hammered.

what size diff is in the 200?? always figured it was about he same as a 100

 

[cruiseroutfit]

what size diff is in the 200?? always figured it was about he same as a 100

Similar but the housing strength likely comes into play. I'll snap some pics!

 

[jLB]

I realize that the 98-99 models have a weaker 2-pinion front diff, but I have to wonder, if the lack of ATRAC, doesn't also contribute to the 98-99 diff failures, since front wheel spin would be unchecked by any electronic nanny?

 

[SocalLCruiser]

I broke my 2003 front diff. Wheel Spin and sudden traction....equals $$$ spent.

 

[thebeedeegee]

If this happens on the trail, do you just pull the front shaft, then both CV's...lock the center and drive home?

 

[ClassyJalopy]

If this happens on the trail, do you just pull the front shaft, then both CV's...lock the center and drive home?

Pulling CVs isn't necessary. Much easier to just pull the hub flanges. Once the front drive shaft is removed, you can lock the CDL and drive in RWD mode!

 

[thebeedeegee]

Pulling CVs isn't necessary. Much easier to just pull the hub flanges. Once the front drive shaft is removed, you can lock the CDL and drive in RWD mode!

but wouldn't the CV's still (very slightly) turn the diff gearing and make a bunch of racket?

 

[ClassyJalopy]

but wouldn't the CV's still (very slightly) turn the diff gearing and make a bunch of racket?

They usually don't. They are riding on a needle bearing at the wheel hub.
Another option to get manually lockable front hubs from @cruiseroutfit and just unlock them when this happens!

 

[lt1fire]

So I've since sold my 100 but the front diff did just bust out on the new owner. He's getting a new R/P and installing the TJM locker I never got around to doing.

 

[nukegoat]

Similar but the housing strength likely comes into play. I'll snap some pics!

It's a 9 instead of an 8

 

[CorporalClegg]

Sudden traction in snow, in reverse caused my 99 R&P failure. high mileage and severe tooth wear (excessive backlash) is what I believe contributed mostly to the failure.