A-TRAC/TRAC/AUTO LSD Explained (Easy to understand, I hope!)

David has done a very good job of explaining the traction systems

Toyota should offer the locker and ATRAC systems as an option on all configurations , maybe in the 3rd gen

 

As I said, nothing in my purchase paper or window sticker says 'short bed'... as the 5 ft. bed on a double cab is the normal (standard) bed length. The option is a 6 ft. bed on non-off road double cabs, and it is called 'Long Bed' but only on double cabs, since 6 ft. is a normal bed in all other Tacomas.

 

Glad we agree that the 6' bed on Tacoma's is the normal bed

 

Yes, on all Tacomas except double cabs where (only) it is a long bed.

 

Having the mutant bed on a DCSB does make sense for keeping the wheelbase the same as an AC , but I would suggest it is as much to do with having the driveshaft length the same for a manual transmission as it is to limit the length of the double cab . The 2nd gen TRD Offroad model was most likely designed around the AC platform with it's Tacoma standard 6' bed , and then the engineers tried to figure out how to squish s DC cab onto that frame , the only place to reduce is the bed length . If they really wanted to make the ultimate TRD Offroad based on wheelbase alone they would do a Regular Cab version .

Having said all that , it's too bad Toyota doesn't offer the Offroad features like a locker and ATRAC on the DCLB , as this would expand the purchaser's options .

 

sorry if this is a stupid question, total tacoma newb (I don't have one yet.)
What limited slip function (if any) is available in a 2wd model? (not a 4x4) I currently have a 2wd ranger with an open diff and it drives me insane. wondering if a 2wd Tacoma 2005+ has an LSD and later an ATRAC option? or if the cool stuff is only for the 4x4s... looking on the site it appears the 'locking rear' is only an option on the 4x4.

 

all 2009+ Tacomas (2WD):

1) TRAC (limited slip traction control provided via the ABS brake system and engine regulation aka throttle control) is the standard mode you are in automatically.

2) AUTO LSD/TRAC OFF (limited slip traction control as above, but there is no engine regulation, brakes only for more power to move you ahead).
Activate with a quick push of the VSC button moving or stopped.

3) REAR LOCKING DIFFERENTIAL (only on the Off Road TRD Tacomas).

As said above, there was a brief flirtation with mechanical limited slip differentials in 2005-2008 Sport TRD Tacomas and some others.

Not sure why Toyota dropped that feature? Replacing brake pads is cheap and easy compared to rebuilding differentials for the LSD clutch pads.

 

As a long time winter driver and off roader and owner of a a Tacoma with the of road package; a locking rear differential is of limited value off road when you have trac and Atrac and almost no value in winter conditons with ice and snow. Having a locker seems to impress a lot of people but to be blunt, I never missed it with the Atrac on my previous 4 Runner. A rear locker is just a temporary max traction get out of jail free move and only useful for longer intervals up continuous steep terrain to avoid over heating brakes.

 

I predict the locker will go the way of the dinosaur once we are are all on board the A-TRAC train. When I traded my '05 Off Road 4x4 for the 2010, I had not heard about the traction systems. I ordered another Off Road simply because it has a rear locker. Until everyone understands how A-TRAC works, I think the locker will remain available. Once everyone knows that A-TRAC give more traction (as it works on the front and back tires) than the rear locker, you may see it gone?

I have only engaged the locker (with A-TRAC always on on L4) when I had to pull stuck 2WD Tacomas, and in snow (to not cut the throttle above 3 mph). I may have pulled them without the rear locked, I don't know? Generally you only want to get it right the first time! LOL

I guess in an ideal off road world, we would have front and rear lockers as well as A-TRAC for all the choices. However, actual need/ use and cost would be reasons not to. That the A-TRAC doesn't compromise steering and the lockers do has me think A-TRAC will replace lockers on a safety basis alone. Just one yeh-hoo going over a cliff locked and then suing Toyota is all it will take!

 

so these definitions would apply to the 2016? Would atrac/trac be mts in the 2016. Just trying to understand all of this, ie my first 4wd vehicle and toyota didn't make it terribly "simple", as for crawl control.......don't think I will ever use it, I'm kind of a control freak on some things.

 

Awesome!!

 

A-Trac comes with the Manual Transmission TRD Off Road and will honor all of the stuff laid out in this post. The Multi Select feature is brand new (to Tacoma) this year and will need to be added as further options to know about. If you have the 2016 TRD Off Road you'll need to learn the new nob setting for specific conditions, though it is ultimately using the A-Trac functionality to accomplish your needs in each specific application.

That being said, I'm not sure what is added into the mix to make it better in sand or when doing a super steep ascent/descent and how you'd get the same results with A-Trac.

I'd love to see some example videos or descriptive posts of people using the "old" tech to accomplish the same thing the "new" tech promises, the "getting unstock after being buried in sand" videos that seem to be everywhere when you search for "Multi Select Tacoma."

 

I just picked up my brand new truck today. I had the guy check the u-bolt and grease the joints and check the transmission as that was my focus while at the dealer. I get home and cannot find an A-trac button and when in 4 low its says trac off. I have the 16 off road with a auto trans so do i not have A-trac or is there a way to not have it on an offroad version??? Does this also mean that i should be looking at doing the yellow wire mod???

 

Calm down, all is well, you have A-TRAC, it's just that in the 3rd gen they call it MTS. See the button and the big round multi-position knob on the roof above your head? That's MTS, that's your A-TRAC. Same idea. And yes, in 4L you have no TRAC (traction control), that is by design. And for the love of all that is holy, don't go cutting any wires

Let me re-paste the @David K cheat sheet that has been created for 2nd gen, it's basically the same thing for 3rd gen (I need to verify some 4L settings, but it should be identical):

Press Nothing...

H2= TRAC (Limited Slip with Engine Output Regulation)
H4= TRAC (Limited Slip with Engine Output Regulation, front and rear)
L4= No Traction Control
---------------------------------------------------------------------------------------
Quick Press (VSC OFF SWITCH) moving or stopped...

H2= AUTO LSD (Limited Slip without Engine Output Regulation, VSC OFF to 30 mph)
H4= TRAC OFF (Limited Slip without Engine Output Regulation)
---------------------------------------------------------------------------------------
Press and Hold In 3-5 seconds (VSC OFF SWITCH) while stopped...
H2= VSC OFF (No Traction Control)
H4= VSC OFF (No Traction Control)
---------------------------------------------------------------------------------------
Off Road TRD:

Quick Press of RR Lock Switch = Rear differential Locker (L4 only on 4WD models)
L4 Only: Quick Press of A-TRAC Switch = Front and Rear near-no slip traction control. A-TRAC works the front below 3 mph when the Rear Locker is also on.
==========================================================================

What should you use?
Standard Mode until you lose traction, then quickly press the VSC OFF button to increase the power of your traction control (more engine RPM, stronger braking on the spinning tires).

In L4 (Low Range) and your tires spin, press the A-TRAC button (Off Road TRD only) to nearly lock-up any spin. I always have A-TRAC on in L4... unless you need to spin the mud out of the tires.

Emergency stuck if A-TRAC doesn't work in any situation, press the RR Lock button (works with or without A-TRAC working on the front tires). The rear locker connects both rear tires from inside the differential (0 spin). Turn off RR Locker, once you are unstuck.

1) H2 TRAC
2) H2 AUTO LSD (VSC OFF to 30 mph)
3) H2 VSC OFF
4) H4 TRAC
5) H4 TRAC OFF
6) H4 VSC OFF
7) L4 VSC OFF
8) L4 & A-TRAC
9) L4 & Rear Locker
10) L4 & Rear Locker & A-TRAC

 

So it would seem that in 4L where i can lock the rear dif i have no traction control so i have an open front? This is the only reason i would worry about atrac. I plan on gong out to play soon i just saw in the book that came with my truck there is an a-trac button and i dont have one. So with the terrain select put to rock which is the most restrictive that would cover the front? Spent a lot of time studying this thread prior to getting my truck during the long wait so i have obviously not had a lot of time to play.

 

Yes, your front diff remains "open" and the computer uses the brakes to create a tight LSD in the front when you use MTS. It does the same for the rear actually, but if you lock your rear diff, it's a physical locker and thus completely locked. So what you're describing there is #10 from the list above.

 

sweet i understand lockers from my time in a fj40 with my dad, but the new electronics are still a little fuzzy. Thanks for the help.

 

John, you have an AUTOMATIC... and in 2016, then automatic off road 4WDs DO have A-TRAC, but no button... it is incorporated into the MTS system (multi-terrain select).

So, please go play with your new Toy and report back to us on the various terrain select operations.
You should be able to notice that during loss of traction (when one or more tires spins) the spin will be halted as power is transferred to the opposite tire on that axle in a manner that BOTH will turn together... just like if a locker was on the axle.

In A-TRAC, L4 driving, your truck feels like a Sherman Tank in that nothing stops it, not even if three of the four tires don't have traction! You should have the same feel in MTS or CRAWL... Just point the truck with the steering wheel and let it crawl over or up anything (that won't cause damage of course)!

 

Right... so DO NOT use the Rear Locker as a first choice, as it will limit the traction features unless you are under 3 mph/ or stuck. The Rear Locker is for EMERGENCY unstuck (per Toyota) and yes, I know it works all the time in L4 if you turn it on. The point is, you should not need to... keep it as you ace in the hole IF the normal traction features (which do not hinder steering like a locker does) fail and you do get stuck. Since A-TRAC, I have never been stuck or needed the Rear Locker... I only use it to test it and see what it does differently than A-TRAC alone. Remember, I owned two other Rear Locker equipped Tacomas before the A-TRAC Tacoma, so I am very familiar with locker use.

 

Love it! About a week after I bought my truck I spotted a power line access path going up a decent sized hill. I was on my way to a friend's wedding and had a fresh hot coffee in hand but I couldn't resist my first off road opportunity in my shiny new taco. It was a slick stone base with 2-4 inch rocks covering it. My Inclinometer thing pegged at 30 going up. Wouldn't do it in 2wd in any mode. 4hi was getting me there and I think I could have made it but I wanted to play with all the modes. 4lo made it cake but would still slip a bit on the loose rocks. Crawl control was awkward. Pretty jerky (almost spilled my coffee!) and lots of noises, but effective. MTS was the magic maker though. I set it to loose rock and it crawled up and down the hill effortlessly. I didn't mess with the locker or the ect power but from what I understand the ect power just allows the engine to rev higher before it shifts. Love this truck! I'm going out to play all day tomorrow so I'll try to mess around with all the different modes.