AUTO LSD (or Not) for added traction in 2WD?

Is that what the truck in the video only used?

 

If so...wow!

 

Back when I had my 2005 2wd Ram with limited slip. I had to do this when pulling out of a wet field with goodforayears. It actually helped.

 

Yup trd sport pre runner

 

Auto lsd helps. But is no where near a locker or posi...

It has to detect when spin and when it does it transfers power. So in the snow, when one wheel has enough power to break static traction odds are the opposite will too.

Now a posi and locker always distribute torque evenly so your tires are much less likely to slip into dynamic traction.

Another huge drawback is that this system works by incurring heat on one brake to transfer mechanical energy against the gradient. Which means your engine will lose power to propel you when you need it, for it is being dissipated through the brake system.

This is worse that Chevy's auto locker. Chevy's auto locker locks when a spinning tire reaches a certain delta figure. Then the two lock together through an internal clutch pack. In principal it's just as bad since it spins like a crazed ape on snow. But it won't eat your engine power which is a HUGE factor is some of road situations.

I drove my taco from 1000' to 9000' going over San Bernardino mountains all off road while it was snowing. And sometimes turning alsd off helped cause I need the wheel spin and the loss of power was too great at altitude.

 

You must of had aam's torque sensing type differential. It applies a multiple amount of torque to the wheel that has better traction.

When one wheel comes off the ground. Any multiple of zero is 0. So you apply the brakes and now it stimulates traction and applies the multiple of braking force to the tire with the most traction.

Torsen invented... dodge borrowed.

 

No comparison between a locker and auto lsd.

Sorry. Have a hacked locker and may engage it on the freeway if I want.

Locker prevents slip from happening. Auto lsd tries to limit slip.

A posi will blow auto lsd out of the water if it is setup correctly.

 

I assume this is directed towards me.

I wheel in glamis. Pismo beach... I use 2wd as often as I can get unstuck with 4wd. But in sand wheel speed is a huge deal.

Yes it will brake the spinning wheel. But then the power that readily spun your wheel is transmitted against the energy gradient (energy flows through path of least resistance) and in turn spins your opposite wheel.

A locker or posi would send split torque and instead of one wheel attempting to move you. You have two and if one tire wants to spin, the opposite tire lends traction to it because the both spin together locked.

Physics wise, auto lsd is a joke for off roading and is for light trail use and streets where one wheels friction coefficient is suitable. Doing anything above light is risking drive train parts with immense amounts of stress. Just think about how it's done. All the stress on the spider gears. On the brakes. On the internal bearings having load jump around violently.

Other lsd stress the system too. But different parts that are usually much stronger. Like half shafts axles. Ring and pinion gear. Stuff designed to handle power all the time.

 

well yeah but no also


having the systems in place that can do AutoLSD via braking means
you also have other trac and stability modes a posi cannot do for you

so, yea focusing on just what is happening in the pumpkin, fine, posi
is better than autoLSD...but I will take autoLSD and the brake controller
system over any old-skool non-computerized any day any where.

Unless you are talking about a moggie. I would take a moggie and throw my Taco away

 

Sub'd, I need to read through this as I didn't seem to see much if any improvement w/ A-LSD engaged on my truck. All snow/ice situations.

 

I don't want to derail this thread, but I'm not following you on the part saying that AutoLSD stresses the "system". Other than the brakes which are being used in the 09+ tacoma's to create an LSD, how is it putting any more stress on any of the parts than any other circumstance? The path of least resistance is changed for the power, so most (if not close to all) goes to the non-spinning wheel on the axle.

Back on topic...I know I've read it on here before but don't remember specifics. People have said that they were stuck, couldn't get 4wd to engage, and AutoLSD got them unstuck. Anyone with similar experiences?

 

Simple. Lift rear axle of your pickup. Block one wheel from roatating (dont set parking brake), than grab the other wheel and rotate back and forth. Hear clunk? Thats everything from axles, spiders and ring and pinion getting beating
That electronic system was made to save you on your way to mall. Beating on the trail will result in catastrophic failure.

 

The brakes of our trucks (and most cars) are made to be used much greater than we will ever need to (we hope). The brake pads are a relatively easy item to replace and part of the normal maintenance. Using the strongest component to achieve better traction is smart.

Putting extra strain on gears, that are far more expensive to replace, doesn't seem as wise, and a bit old fashion with this new traction technology being so widely utilized by top auto manufacturers.

Maybe instead of insulting Toyota technology with your Mall comment, you should accept that tens of thousands of Tacomas made after yours has AUTO LSD and TRAC, while the mechanical LSD was discontinued before 2009.

 

Maybe you should spend more time wrenching in garage to actually know what you talking about.
First Toyota ditched mechanical LSD for cost cutting (electronics are manufactured in China for dimes) Mechanical LSD we had is still manufactured in Hino for their large trucks.
Second. VSC system you have is common Bosch made for passenger cars. ATRAC is additional code with relocated pump. So yes its "Mall future"
Third: Brakes slow down the wheel, true but strain is on everything else. If you hammers gears long enough you will split R&P, bend something or simply eat splines. Everytime truck applies the brakes other parts gets hammered to move load to other side. Thats how it works. Thats how people break their axles and their CV's.

 

Ok amigo... no flexing with you on the future here.

If there was no such thing as A-TRAC then I would order the front locker if it could be obtained by the dealer, otherwise, ARB, right? It is just so sweet A-TRAC does work off road, and we don't pay more for it than we did for an Off Road TRD before it had that tricky device!

Now have fun!

 

A Trac works excellent

It's extremely sensitive and allows great maneuvering.

But now you're diverting torque across gears that is magnified from low range.

But since you're moving at a crawl I believe it helps a lot more than auto lsd. Since your car is not utilizing wheel speed and power. It's too crawl over things.

These trucks aren't Rubicon's. So let's stop thinking they're.

Low range rear locked is extremely good traction. I only use atrac on sand covered rocks. Where a locker would stress the tiny 8 inch diff going from high to low to high traction.

 

so if i follow you correctly the sport doesn't have stabilitrac because it has a posi? actually asking not sarcastic.

no, a well set up posi only makes the tires spin at the same rate off road. but in high traction situations it will allow individual wheels to rotate faster for turning. so traction control can still be in place and working

its not ONE OR THE OTHER... But I understand you saying you would rather have electronic over mechanical if asked. But my old high hp twin turbo cummins didn't have traction control and would spin its posi dana 80 getting onto the freeway. I never once thought trac would be nice

btw, abs sucks off road, where sometimes you need to lock the tires to dig in and stop faster (terrain dependent)

and you're disregarding the fact that a brake system doesn't solve the problem with an open diff. power flows through the path of least resistance. so you have to brake a wheel hard enough to make the other wheel have equal or less traction (less traction is way more likely) so you're just throwing torque left and right and not splitting it to both wheels equally. which a clutch pack or gears or mechanical locker can do.

but in ice, having one wheel spin instead of two is better, you sway around far less.

so you may be correct if you're trying to state no system has no downfalls

but for this threads sake, auto lsd is a cheap gimmick that can't match the off road performance of a true lsd.

and I don't allow any vehicle stability control on my vehicles off road, it has never saved me, only compounded problems.

moggie? the mercedes unimog?

in a differential, you have gears called spider gears that allow the axle shafts to spin in opposite directions... it sits inside a unit that houses it and is connected to a ring gear which is spun in one direction via a pinon (driven directly from the driveshaft). when wheel spin occurs, one shaft stays still, while the until spins around it, the spider gears will now do there thing and let the other shaft spin in the OPPOSITE direction which is forward.

imagine all that coming to an abrupt halt, and all the power must be transmitted through the spider gears, for thats where the power is transmitted via when you have wheel spin.

a posi, its a clutch pack and springs that sits inside the spider gears and pushs against everything to attempt to make them spin together, or resist spinning away from each other.

auto lsd can get you unstuck, it tries to use the best wheels higher friction coefficient. but can't use both wheels in tandem like a true lsd

the braking system on any car would not need to be beefed up. stopping a car 4000lbs at 100mph would incur exponential amounts of heat than slowing a spinning wheel.

they may have, but it is unnecessary to do so.

and you're skipping the inherent problem that these systems can compromise your axles longevity.

its cheap, a true lsd will stress the strong parts of your axle, but auto lsd directly stresses the biggest weakness which is the spider gears, they are physically much smaller and when wheel spin is occurring they can't stress the center section enough to alleviate there own stress and will break prematurely.

this is what typically breaks when people do 1 wheel wonder burn outs.

when you have equal traction, the spider gears lock the axles together and the center section will propel you, and when one wheel losses traction, the spider gears will start to spin.


i would rather replace a clutch pack than the internal gears of my diff because I wanted a cheap and effective auto lsd


look at this

http://www.youtube.com/watch?v=gIGvhvOhLHU

 

Thanks for the time you spent adding your detailed post.

The only comment to yours is that it would be a gimmick IF it didn't work. The truth is we don't have limited slip inside a differential or a front locker offered, so without going after-market, the reality is TRAC, AUTO LSD, and A-TRAC is what Toyota installs now. My hope is everyone who has any or all of these Toyota features will know how to use them and that those who don't (yet) have them, stop bad mouthing them as if we newer Toyota owners have a choice in what the factory installs.

Is Nissan, Mitsubishi, Suzuki, or other mid size truck companies where you will go instead of having a TRAC/AUTO LSD/A-TRAC equipped truck?

I think all vehicles now have some form of TRAC and VSC... as it has proven (or convinced) those in charge that VSC is the next best thing to seat belts for safety.

A-TRAC adds so much more to the standard 4WD Low Range, that I seriously can't imagine anytime I would be in L4 without the A-TRAC on standby. If you don't want it controlling spin until you are stuck or almost stuck, then engage the rear locker... that way, A-TRAC will not operate until you are under 3 MPH! In other words, conditions have halted you from moving forward over 2 MPH. A-TRAC comes alive and turns the front tires into useful traction grabbers instead of one tire spinning freely.

Again, thank you Jordan!

 

Gotta 09 Reg. Cab Prerunner and i would be stuck a lot more often if it wasn't for Auto LSD.
I've gone to Ocotillo Wells and was stuck once due to not enough momentum in super soft sand and the fact i didn't know where the trail went. Here's a pic of that stuck:
Took my truck to Otay Mountain truck trail a few months back and went on a side road that was clearly not meant for my 2WD and started spinning my tires going up hill, one push of a button and up and over she went with not that much more of effort.
Also took it out to TDS this last March and was goin all over the place out there in Truck Haven. Got hot headed and wanted to do some blind climbing and didn't notice how this hill was shaped more like a triangle and got high centered. Got out of that by Auto LSD doing its job and airing the tires down more to 15psi and some help by a few rocks around the tire. Heres a few photos of that:

and me off triangle-high-center-hill:

i know its not a 4wd but every now and then its got the attitude of one.
Oh and David K, you've been extremely informative every time you speak up about a subject! Keep it up i need to learn more! Those trips you take down to Baja look like a blast and a piece of heaven

 

yea i read that one about a month or 2 after i got stuck! dummy me probably will do it again and get stuck again tho