Reliability called into question (1 Viewer)

[TheLCProject]

In th TFL video the revs seemed to be low at first then he took it up a bit more and seemed to hold it steady for a bit, then you hear the noise/pop and see the front wheels stop spinning, and then the revs run away, but only after the failure and then he shuts it down.

Also notice how the front end dives down as/after the pop occurs.

Hard to tell if there was a lot of skinny pedal involved or not..but wheel speed wasn't really that high from what I can tell.

Now if ATRAC is braking both wheels hard on and off to find traction and slowly braking them harder and harder as engine effort climbs until a failure..

The front left wheel wasn't spinning much, if at all, faster than the front right wheel.


You'd think that there wouldn't be much load on the drivetrain because there's no traction, but ATRAC binds up the wheels by braking them. CVs appear intact from the photos and there wasn't grinding afterward (so maybe not in the diff itself).

My guess is the axle shaft broke, either on the part that gets inserted into the diff or in the tube extension shaft part.

 

[Jstawgn]

This is good publication. That 2.4 Turbo generates soo much more torque. It requires mandatory free upgrade to 8.7" front diff and 9.5 rear diff for all.

 

[2021 LC200]

Looks like the 80, 100 and 200 series long term value has just been reconfirmed

 

[MeWantLC]

I did not watch teh whole thing, just the section where it pops. And a one more time rewinded it. I can only think it it was me and family, alone, and... pops, LOL. Oh S****. Nothing seems out of the extraordinary here, really... so, yeah, a bit concerned about the pop !

 

[UZJ100LC]

Looks like the 80, 100 and 200 series long term value has just been reconfirmed

100 series has been plagued with this issue especially the early years. Although it’s not THIS bad

That’s why front lockers are recommended

 

[2021 LC200]

100 series has been plagued with this issue especially the early years. Although it’s not THIS bad

That’s why front lockers are recommended

Which issue? Just driving over some rounded rocks with some snow and ice, wheels slightly spinning and then you lose half of the 4WD system...? Seems pretty unique. I know 80, 100 or 200 series can be broken during serious rock crawling and jumping of the wheels or as a result of aftermarket lifts and angle on the CV shafts or otherwise, but a new stock vehicle on some lightly undulating ground is a bit shocking. Hope TFL will shine some light on the reason for this.

 

[UZJ100LC]

Which issue? Just driving over some rounded rocks with some snow and ice, wheels slightly spinning and then you lose half of the 4WD system...? Seems pretty unique. I know 80, 100 or 200 series can be broken during serious rock crawling and jumping of the wheels or as a result of aftermarket lifts and angle on the CV shafts or otherwise, but a new stock vehicle on some lightly undulating ground is a bit shocking. Hope TFL will shine some light on the reason for this.

The issue of blowing the front diff after ATRAC actuates and instantly transfers power. Or with sudden gaining of traction. Usually happens with poor technique like wheel hopping. It’s not this bad as this scenario but the issue is known to happen

 

[TheLCProject]

The issue of blowing the front diff after ATRAC actuates and instantly transfers power. Or with sudden gaining of traction. Usually happens with poor technique like wheel hopping. It’s not this bad as this scenario but the issue is known to happen

Not saying this is a thing but just something: 100 Series Front Diff Failure - Random Chat - https://forum.ih8mud.com/threads/100-series-front-diff-failure-random-chat.1075641/

 

[TWILLY]

Yeah, wheel spin to sudden traction in snow and ice can destroy front diffs. Interested to see the diagnosis here and whether this becomes a common problem.

 

[TheLCProject]

Yeah, wheel spin to sudden traction in snow and ice can destroy front diffs. Interested to see the diagnosis here and whether this becomes a common problem.

Or wheel spin and sudden ATRAC braking?

 

[2021 LC200]

The issue of blowing the front diff after ATRAC actuates and instantly transfers power. Or with sudden gaining of traction. Usually happens with poor technique like wheel hopping. It’s not this bad as this scenario but the issue is known to happen

Yes, seen it on videos of significant rock crawling with 4 x 4's including a case with a 100, but this was just about the most benign situation. Lets see what TFL reports back.

 

[TWILLY]

Or wheel spin and sudden ATRAC braking?

Yep.

This sort of stuff gives me warm feelings for the elegance and slowness of selectable lockers. All of that wheel spin and throttling seems violent, just begging to break things.

 

[TheLCProject]

Yep.

This sort of stuff gives me warm feelings for the elegance and slowness of selectable lockers. All of that wheel spin and throttling seems violent, just begging to break things.

It's like a fatigue test...

 

[Jetboy]

They should be able to flog the s*** out of MTS/ATRAC without thinking twice on basically any terrain.

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[jayp2]

My post said "It does look like the failure was at least partially A-TRAC related". I'm not convinced the ATRAC killed it or did not kill it and am not trying to convince you of that either as we have limited information to go on .

If we want to get in the weeds, it's a causational observation as A-TRAC was clearly engaging multiple times in the moments prior to the death of whatever component broke. If that component is behind the front pinion....probably not A-TRAC related. If it's after the front pinion you, Toyota, or someone else would need to convince me that A-TRAC wasn't at least a contributing factor as it was literally the only shock loading being applied to the axle at that time (although we both agree it should never have broke and therefore probably can't be the main cause of death).

FWIW I have a nanny-off button on my GX that complete kills A-TRAC. I think it's a lot safer on drivetrain components in the snow, in addition to being more fun. I really dislike the sensation of A-TRAC clamping down on a fast-spinning wheel and immediately directing 100% of the power going to that axle to the other wheel. It's fundamentally a reactive system as it allows vehicle speed to slow down and then causes the abrupt power transfer. A locker would not lose traction to begin with.

Not digging at your theory at all

I'm just not seeing how the stress that ATRAC would cause at the brake rotor/end of axle is fundamentally different than that of a spinning wheel suddenly getting traction on ground.

I cant stand the sound of it enguaging.....makes my skin crawl like nails on blackboard.....

 

[M1911]

Pretty sure my local dealer told me there was a hood placed on all Tacomas last week.

I don’t understand what you are saying here. What do you mean by “a hood placed on all Tacomas”? Are you trying to say that Toyota placed a stop-sale order on Tacomas?

 

[elpeyote]

I wish they had taken the time to look to see if the front axle was still turning when power applied......would have at least told us if the issue was xfer or forward of xfer

From these guys? They were under there looking for leaking headlight fluid.

 

[carboncycles]

I don’t understand what you are saying here. What do you mean by “a hood placed on all Tacomas”? Are you trying to say that Toyota placed a stop-sale order on Tacomas?

Yes, I think @Corbet meant hold...there appears to be several recalls and holds being announced from Toyota (GM has a very big one on immediate stop sales for the Canyon because of a major software issue...yikes)

 

[Phillyd2]

Not digging at your theory at all

I'm just not seeing how the stress that ATRAC would cause at the brake rotor/end of axle is fundamentally different than that of a spinning wheel suddenly getting traction on ground.

I cant stand the sound of it enguaging.....makes my skin crawl like nails on blackboard.....

I'm sort of thinking the same thing - that ATRAC would be more forgiving and 'gentle' (for lack of a better word) than Front Lockers. ATRAC does have a speed limiter which I *think* is even reduced when the rear lockers are engaged.

 

[Phillyd2]

If some regular guy had this happen to him and came on this forum to get advice I'd be much more concerned. Something about some dudes with a YouTube channel and 500k subscribers posting this on a video... This is the kind of stuff that happens that draws a lot of attention and that's exactly what they want because it makes them a lot of money.

The good thing about someone with lots of views and subscribers is that it will be much more likely to be noticed by Toyota, where if it happened to you or me it might be ignored or dismissed as a one off. Even if this was a one off Toyota would be more likely to address it.