TRD Pro or Limited

@4X4Runner, thank you. Now I get why in the videos I've seen on this topic, only the locked rear differential immediately gets the stuck 4Runner going.

 

One correction...I was looking through the 2019 4Runner eBrochure and when you get the AWD Limited rather than the 2WD version, the Approach/departure angle (degrees) is the same 33/26 for the OR. ORP, and Limited.

 

I’ve searched for descriptions of how different 4Runner trims handle wet (from rain, not snow) streets and roads, but most of what I found pertains to snow. I’ve assumed the Limited’s AWD is best, but not sure how much it adds to all the Star Safety features on wet pavement.

 

The biggest difference you might feel from rain wet roads will probably depend on the tires more than anything else. My pro came with nitto terra grapplers, and they’re great in everything except mud.

 

People get caught up on rear lockers, it's nice, but over rated. It's old school thinking that locked is better than open. Electronics have all but eliminated that performance gap. For example did you know that McLaren only uses open diffs, even in the P1 hypercar they use electronics and the brakes to lock the rear, obviously its a more advanced system than ATRAC but principal is the same. Power goes to the wheel of least resistance, so a slipping tire will continue to slip. Mechanically locking it forces both wheels to spin at the same speed, applying the breaks to the spinning wheel forces power over to the other side where the wheel has traction, the system applies the brakes to individual wheels as needed until the wheel speed is matched - in essence doing the same as locking the diff. The downsides are minimally increased brake pad wear, your technically wasting/losing a small amount of power to the brakes, and overusing the ABS/Traction control systems can overheat the brake fluid and cause fade. That being said you have to be giving the vehicle one hell of an epic beating to actually overheat the brakes/brake fluid using ATRAC, its possible but I've never actually heard of that happening, ever, to anyone. The one place a physical locker really has an advantage is when submerged in mud or water because the brake system will have reduced friction.

 

https://youtu.be/50HzDfO0134

 

I don't feel I have the offroad or technical expertise to make a robust counter-argument. I do know that video evidence can be found online to bolster many different "here's all you need for offroading"or "this feature is better than that feature for getting unstuck." One example: https://www.youtube.com/watch?v=R14V07FHNlw ... and many videos seem to demonstrate that the Off Road's array of tools increase chances of tackling various traction-loss problems, such as https://www.youtube.com/watch?v=FW2ZD_zeUvo ... I have no idea of the level of correlation between what McLaren does with vehicles like theirs and a 4Runner stuck in a rut ... Anyway, I really enjoy your "Agent_Outside: Adventures in a 4Runner Limited" thread.

By the way, is that the front bumper for your year's Limited--or aftermarket. I like it and I don't like all the flashy chrome on my 2019.

 

The correlation is that a hyper car manufacturer using electronics in place of a physical locking limited slip diff and if it’s the preferred route for a P1, it’s fine for realistically anything you’re ever going to throw at a 4Runner.

ATRAC and traction control are 2 separate functions that both use ABS but operate differently. Traction control keeps a wheel from spinning, ATRAC keeps all of the wheels moving at the same speed which is essentially locking the diffs without the use of physical lockers.

It’s like saying hold this item up with your hand. Your right arm may be stronger than the left arm, but if either one can accomplish the task of holding what you need to it doesn’t really matter which is stronger. In the end you want the moving moving at the same speed regardless of wether it’s done physically or electronically. I’m not saying ATRAC is better, it’s not, I’m just saying it’s certainly adequate. It’s an advantage on paper, not so much in actual practice.

All the pre facelift Limiteds and SR5s came stock with the same bumper I have. Only the trail got something different. 14+ the Limited got its own specific bumper with all the chrome.

 

@4X4Runner, that's the sort of thing that's contributed to my ambivalence about my choice of the Limited. I'm thinking I'm not dead-on accurate about AWD and ATRAC and H4L. I like the idea that, as happens here the SF Bay area, I'm driving down 101 and it starts to pour and I've got whatever extra traction AWD provides-- but I've had many RWD cars and never had a problem driving in the rain at highway speeds, so I've ended up wondering is it's over-hyped. My son took the Limited up to Tahoe during one of the heavy snow weekends and just shifted into H4L when he hit snowy, slushy parts of the highway. If I'm understanding the H4L correctly, it's different from ATRAC, in that H4L locked the Torsen center differential so 50% of the power/traction was going to front and to the back. You wouldn't use ATRAC in that case, even if traffic was going slow, right? The H4L would sort of replace the open center diff AWD and provide better traction? @Agent_Outside, I appreciate your explanation, not just as part of my learning about all this, but also I'd rather not keep wondering if I should have gotten the Offroad Premium. I've been looking at some of the ORV parks and sometimes they say you have to have a locking rear diff to be allowed on the moderate/difficult trails. That kind of bums me out, when I read that. Am I correct that A-TRAC detects when one or more wheels have lost traction and automatically applies the brakes to the wheel with no traction, allowing it to send power to the wheel with traction? Are there specific driving challenges where ATRAC is better than H4L, and vice versa? And what about "crawl control"? In some videos, even ones by professional offroaders, like Fast Lane Truck, they will say "I'm not sure I could have traversed that area, or gotten unstuck, without crawl control.

 

No argument with "The correlation is that a hyper car manufacturer used electronics in place of a physical locking limited slip diff." If that's what they did, then that's what they did. The second clause in the sentence is, as I'm sure you know, an interpretation, not a fact. Maybe mechanics/technology designed (according to McLaren, the P1 was built to deliver a sub-seven-minute lap of the Nordschleife, which is the 12.9-mile track in northern Germany with 150 corners and 984 feet of elevation changes. It’s tight and bumpy, with crests sharp enough to cause a car like the McLaren P1 to leave the ground several times during a fast lap). And I know the McLaren P1 also was tested at the Arctic Circle, where the icy surface of a frozen lake proved a good location to put the advanced stability control systems through their paces. I'm still not sure that means the McLaren's traction and stability control system could power it (or any vehicle) out of a challenging dirt/rock road rut or a situation where all four tires were spinning in sand, etc. I don't know McLaren's electronics couldn't do anything 4Runner's crawl control and locking rear differential, etc, can do; but I suspect it's never been tested, so I'm only willing to grant that you might be right. However, if I was heading with my wife and kids somewhere out in the "wilderness" (or even a difficult route in an offroad park), I wouldn't bet our safety on that hypothesis. That's all I'm saying about that.

Does anyone know for sure if "ATRAC keeps all of the wheels moving at the same speed which is essentially locking the diffs without the use of physical lockers" is the same as Toyota's description: "A-TRAC detects when one or more wheels have lost traction and automatically applies the brakes to the wheel with no traction, allowing it to send power to the wheel with traction." I don't know enough to say for sure. I had a Chevy Colorado ZR2 and on a few occasions, being able to lock the front and rear diffs seemed like the only way over and out of certain terrains, while my friend with a Tacoma's locking rear diff was also able to follow me, with only a bit more effort. I haven't had a chance to duplicate that route with only A-TRAC.

 

A member nicknamed Kid Vermicious added this useful distinction about the Limted’s “AWD” on a slippery surface vs AWD in vehicles such as. Subaru or Mazda: “As an aside, I noticed you said "the CD will send to the wheels with greater traction". For what it's worth, this is a pet peeve of mine and it's absolutely not true. The ability to actively modulate power to specific wheels depending on which ones have traction is a feature of AWD, and you don't have AWD. You have a full-time 4WD system that Toyota calls "multimode", and multimode and AWD are not the same thing. The Torsen center diff splits torque passively and won't let it all go to just one driveshaft, and your traction control can apply selective braking to wheels that are losing traction or to try and control a slide, and together the two systems can partially emulate a true AWD setup. But they don't come close to AWD in terms of managing high speed traction - they will not actively transfer power away from a spinning tire, and they will not take control and save you from spinning out in a snowstorm and winding up in a ditch the way a true AWD will. I just want to make that point, because I see way too many guys on this board with multimode 4WD who don't understand what they have or what it's limitations are. I worry that some guys (not you necessarily, Bilbo) are making the mistake of thinking they're in a Subaru or other AWD crosssover, and they definitely aren't - the 4Runner is much heavier, with a higher center of gravity, and does not have the handling or slick surface road traction of a true AWD vehicle.”

 

It seems to me that the comments from @Agent_Outside, @kid vermicious, and @4X4Runner frame the Pro (really, the whole Off Road series) vs the Limited debate. What the Limited has, which no other 4Runner offers, is full-time 4WD. On the other side of the ledger are the Off Roads, with locking rear differential, crawl control, and multi-mode selection. If the Limited's full-time 4WD doesn't do much more (on dry pavement, wet pavement, unchallenging dirt road, or light snow) than rear 2WD with all-terrain tires, then it clearly loses appeal points. On the other hand, if A-TRAC really handles most/all off road challenges (including a wheel spinning in a rut or on, say, a rocky dirt hill) as well as the Off Road's and Pro's trio of features, which the Limited doesn't have, then the Off Road series' lack fo the Limited's amenities seems to matter more, that is, if A-TRAC suffices pragmatically.

Not having enough first-hand comparative experience, the "evidence" available to me comes in the form of videos of actual driving situations, but they also can contradict.

https://www.youtube.com/watch?v=d2vb7YuO4sU

vs

https://www.youtube.com/watch?v=KTE8DZqVbUw

 

I’ve been looking at replacement bumpers for my Limited and that trail would save me the expense of having a body shop remove them ... looks like Hollister is about 2, maybe 2 1/2 hours from Novato so sounds like a great idea. I had identified Hollister as probably the closest off road park but couldn’t tell if a stock Limited has much room to roam there. Even if it doesn’t, still would be fun to meet up and see the place.

 

That’s not the case. It’s true full time 4WD and AWD are not the same thing l, but there is no traction situation where the full time 4WD is not better off then 2WD. It may not be actively applying power to the wheels with the most traction but it is applying power to all 4 wheels all the time, without the binding up or wheel slip/drag of a locked transfer case. 4WD will always be superior in situation when your applying throttle. It may not direct power to specific wheels but under acceleration you will always have twice the size of a contact patch applying power compared to 2WD with all else equal.

 

Yes,I meant that as a hypothetical (which, I agree with you, is not true), not an assertion. I’ve always thought almost any version of AWD or (unlocked differential) full time 4WD had to be giving me some traction advantage. I’ve done no off-road driving with pure AWD, but in the 1980s, I did quite a bit with a Jeep CJ7 and a K5 Blazer, in The Colorado Rockies (I lived there then) and last year, a bit of pretty unchallenging time in a Chevy ZR2. So, I’ve read your stuff with interest, since you’re now in Colorado and you’re not just speculating about what the Limited can do. Just reading and watching videos left me debating whether to start building up the Limited or sell it and get an OR Premium. One reason has been that often I found a product I thought would look great and beef up mine, only to find out that “they” make it for all 4Runners except the Limited. The latest one, about which I had gotten excited, is the ARTEC Industries Venture front bumper. Anyway, that has nothing directly to do with what we talking about, but if I continued to find myself stymied in that way every time I see an add-on or replacement part, I have to admit that would influence me.But I haven’t done enough research to know if I could build out the Limited as I’d like, nor if I’d end up concluding it’s fine for the easy-moderate range of off road driving I’d be likely to stay within.

 

Oh, yes, that was actually the one my wife and I read about first. The distance varied depending on where it looked like we’d have to enter and we also thought about driving up to one of the nearby towns the night before we tried out the Limited there, but it would be much more fun to go there with you and some folks who are more experienced with the 4Runner. We’d probably end up being too cautious to really enjoy the day, if we were there alone. We always went up into the Rockies with two other families if we were doing anything challenging.

 

Getting groceries and picking the kids up from soccer...

 

I like how you painted the lower front fascia.........

 

to all T4R the Limited has Full-Time 4WD is just like it says on the box. Not AWD. It’s what we have in the Limited. It’s the full-time version of what I’ve just described for our part time friends (specifically open differentials), but with a major distinction: The system employs a 40:60 torque split in most driving situations and alters that in response to slippage. In addition, if the front wheels are slipping while the vehicle is turning, the  center  differential changes the torque split to 30:70. If the rear wheels slip while the vehicle is turning, the split changes to 53:47. This info is taken directly from Toyota: Toyota 4Runner Celebrates Historic Run with 40th Anniversary Special Edition - Toyota USA Newsroom
*note the section, “4x2 and Two kinds of 4x4.”
AWD, 4WD (part time)

AWD is a system in which each wheel can gain traction independent of the other wheels and their behavior. All wheels are capable of being driven simultaneously, spinning at different speeds, in all grip conditions. Power is sent through the center diff (often with a rear power bias) to each axle, which both contain limited slip differentials. If traction is lost on both axles, all four wheels will continue to receive power and turn regardless of the condition. No 4runner possesses this system. These are our Audi and Subaru friends.

Part Time 4WD system: When engaged, part-time 4WD system sends power 50:50 (front:rear) to each axle, and simultaneously to all 4 wheels. In the event of a loss in traction, power is sent to the wheel with the least resistance. If you have a loss of traction on each axle, power is sent to the wheel offering the least resistance (on each axle), meaning you're basically stuck. This is due to having open differentials on each axle. All 4WD 5th gen 4runners have open differentials on each axle. Only our 2WD friends get an LSD on the rear axle.

You drive around in Full time 4WD(H4F) all the time, but because of the center locking differential on the Limited you have the option of switching into High 4 Wheel Lock mode (H4L) or Low 4 Wheel Lock Mode (L4L); This is the same a part time 4WD with 2 speed transfer case.

 

You bumped a 5 year old thread for your second post. Are you a bot? What's going on?