A-Trac is a must for our IFS

Hmmmm. Not sure. I have a dial knob and its in H4F for regular driving and can change dial to H4L to as my understanding was to Lock the center diff. Then of course there is L4L.

 

Center is locked in our 4Runners except Limited. Wrangler centers are locked too except the Sahara trim

 

I find it funny when people give an edge to the G wagon saying that it has three lockers. I have three lockers too in my 4Runner, two from factory, one aftermarket. The Rubicon has three lockers too

 

You have a Limited, which has a different transfer case than other 4R

 

Yes. Part time 4wd doesn't have a center differential at all, but you're correct in that it's always sending equal power to front and rear when it's engaged.

The limited has a center diff locker, though.

This is correct.

Part time 4wd has no center differential. 4wd is either engaged (locked) or disengaged. The Limited has a center differential to all full time 4wd, which can be locked by selecting H4L, as you mentioned.

 

Any limited owners can chime in on hypothetical situation. in H4F if one front and one back wheel is not getting traction and spinning does the other non spinning wheel on same axel get all the power tranfefed to it or does all the power go to the spinning wheel and essentially leave one stuck unless they use the A-Trac?

 

You're stuck in that situation unless you use ATRAC, rear locker (or front locker), even if you have a locked center diff.

 

You are stuck. Now you could try H4L to see if that helps. The difference being the locked center diff. The same worked for me on my snowy driveway.

 

A-Trac only works in L4L. In H4F there's basic traction control, which will cut engine power and apply brakes to the spinning wheels. In most off-road terrain, basic traction control won't get you unstuck.

 

Ahhhh. Good responses. Thank goodness for 4 low and A-Trac.

 

Even with the center diff locked, if one wheel on each axle has no traction, you're stuck. This is the case with part time 4wd also. This is why locking differentials, and traction aids like A-TRAC are so valuable.

 

What follows is what I’ve gathered from my few years of off-roading experience, and what folks more experienced than me have shared here on this forum. Oh, and you-tube 4wheeling “fail” videos lol.

Seems to me it’s pretty pointless to compare A-trac and a locking diff to say one is better than the other. Several here have already said it well…they are different tools for different situations. If you have both options at your disposal, almost always, one of these tools would be preferable over the other in any specific situation, depending on the trail and the circumstances.

For example, if you know you’re going to lift wheels cross-axle, a locker will move you over that obstacle without any loss of traction and no drama whatsoever. Somebody watching wouldn’t be able to say “wow that locker got you out of that” because you never got stuck or lost traction to begin with. Lockers make for boring youtube videos. Sure, A-trac would have worked to get you moving once you start spinning wheels in the air, but momentum is king (I’m still learning that lesson), and maybe you want to avoid the potential for digging up the trail. So if you have both tools, they both would work, but lockers are preferrable.

On the other hand, if you you’re gonna lift cross-axle wheels on a very tight uphill turn, with mixed slippy-grabby traction…maybe you don’t want to use a locker, because you stand a greater chance of breaking an axle in that circumstance. So Atrac would be my best guess at a preferred tool. But suppose that same scenario now included a 1000ft fall off of a cliff on the outside of the tight turn…now maybe you don’t want to risk any slippage at all…that might make the locker preferable, despite the risk to the axles.

It’s not always possible to know in advance the preferred tool for every
scenario. The better you get to know the tools on your vehicle, the better you’ll be able to use either to fit the situation.

If someone has lockers but is hesitant to use them because they are fussy, or a pain, etc, that just says you are not comfortable operating them for some reason. You have to be comfortable knowing how to work both the lockers, and A-trac, in order to get the benefit of both.

 

A-Trac hasn't failed me even once in over 30,000 miles of exploring, including tight Jeep trails where I had two wheels in the air. I air down, switch to 4Lo and engage A-Trac. When A-Trac finally fails me, you bet I will report here.

 

This example sounds familiar.

Ramp Rock?

 

But I’m not sure what that statement actually means though in terms of a-trac abilities.

I can say the opposite…in the last few years I’ve needed to winch out a handful of times. In those situations, a-trac has FAILED to get me unstuck 100 percent of the time.

But that statement doesn’t mean much, because the rear locker didn’t get me unstuck either.

All my statement really says is that I drove into something that I shouldn’t have driven into lol.

 

Without A-Trac I got stuck so many times I lost count. No I don't even wait, I engage it in advance

 

Lol, ramp rock just scared the shit out of me to be honest, before I even got to considering the virtues a-trac vs lockers.

Once you add height to the
equation, the winch just seems like such a reasonable way travel

 

If you're not getting stuck with A-TRAC, you're not trying hard enough.

 

I've used my winch only once so far, and that to pull a Grand Cherokee stuck in snow. I had my km3s at 8 psi lol

 

A-Trac doesn't like hard trying.

 

So... the brakes are so good they can snap a >1" thick solid steel shaft? Sounds like the stories we used to tell customers that just had to have a reason beyond the reality of shit happens. Not everything has a clear reason but I'm sure they pressed them so they could make a video.

If that is the real reason, that's all the more reason to worry about it because it could happen to anyone.

 

Larger than 1" shafts broke? Are you sure? I thought it was the disconnect?

 

If that's actually what happened then there is reason to worry. It would have been significantly better for there to have been a manufacturing defect. Otherwise it's a design flaw

 

I dunno I refuse to watch TFL and give them views but they said it overloaded the shaft in the post. Point stands either way... if nothing was defective and it broke that means something isn't up to the job whether it be shaft or collar.

Like I said... some customers pressed hard for a why so we just fed them a line of bullshit to get them to move on - I can only imagine an influencer would see the $$$ opportunity of such a controversial video and be even more insufferable.

Defects happen and a shop doesn't have the tools or equipment to give the right answer. Shit happens, just replace the part and move on.

 

Everything has a standard, and a deviation or tolerance. I watched the video a day or two ago. It's not a design-flaw. It is designed not to fail in most situations, but there are situations where it will fail. Everything has a level of tolerance. The circumstance when it broke was outside of the tolerance. It's my understanding though, that it wasn't a CV or >1" shaft. It's a Toyota pick up, not ag equipment.

 

Tolerances aside, I saw a clip on Jeep channel shitting all over it and what they were doing wasn't at all that harsh. They might have done something earlier that damaged it but we'll never know without a full Toyota failure analysis that they would never release. Heavily modified and weighted pickups do far harder trails than where they test it should have no issues in stock form like that. But, like I said, freak shit happens and that's probably what happened here.

 

Every time I get stuck it's always because I'm high centered. Never would have atrac or a locker prevented it only bigger tires would have helped.

 

It was a simple transfer of torque that overloaded a component. It's no different than anyone else in 4WD in slippery stuff, or hopping, or spinning a tire and catching traction. It was really much ado about nothing. Just happened to an "influencer".

ETA: I will say, it probably wouldn't have happened if they had a front locker. Lockers ensure a 50/50 torque split, or 100% to each axle. This happened because there was a torque "transfer" likely of greater than 50%.

 

People break CV axle shafts here and there. But specifically the front diff intermediate shaft is a known weak point on the current gen for larger builds (e.g. 37"+ tires). TFL's Tacoma is on stock tires, but the engine makes 317 lb-ft @ 1700 rpm, and 1st gear on the 8-speed is 4.41 (vs. 3.52 on your A750), so there's a lot more torque going to the driveline than before. As Sheldon says in the video, their design change is a software update to limit torque and MTS/A-Trac more effectively in this situation (which already happens behind the scenes with the various MTS modes).

Based on what they said, possibly 100% of the torque could have gone to one wheel (which is what A-Trac/MTS was designed to do). Roman wasn't doing anything aggressive at all, but the engine was apparently generating peak torque at the time.

 

The 8" clamshell front diff was already marginal in the 3rd gen Tacoma / 5th gen 4R. Now the turbo engine makes a lot more torque at low rpms. Time will tell if Toyota's decision to carryover the 8" front diff (vs. the 9" front diff in the Tundra/LX600) is the right one.