Traction: Better to have it and not need it

... than to need it and not have it!!!

The more traction your truck has the better!

First off, quality tires for YOUR conditions are the first step to gaining traction.

Next, add weight in an empty truck bed to increase traction over the rear drive wheels.

Third, up the level of traction (if you have the equipment to do so).

LEVELS OF TRACTION:

1) 2WD, open differntial. If one rear tire has LESS traction, it will get the torque from the engine... result, spinning tire and then stuck.

2) 2WD, limited slip (differential clutch pack* or TRAC and AUTO LSD). If one rear tire looses traction, the clutches in a limited slip differential or the rear brake on the low traction tire works to transfer torque over to the traction tire. TRAC has engine output regulation, AUTO LSD does not. While the transfer of torque isn't equal between the two rear tires, it does improve the ability to get unstuck. (*'05-'08 Sport TRD)

3) 2WD, rear locking differential*. When activated, torque is divided equally between the two tires. Both rotate at the same rate. Should only be used to get unstuck or cross a difficult surface. Steering ability affected as there is no longer any differntial action (allowing one tire to rotate more than the other, as needed in turns). (*2WD Off Road TRD)

4) 4WD, open differentials. Front and rear drive. The tires with less traction get the torque if traction is less than equal to the opposite tire on each axle. If both tires on the right side of the truck get on ice while the two left tires are on firm ground... the truck stops moving as the two low traction tires spin. Having front drive added to rear drive generally enhances the trucks ability over any 2WD only system. The weight of the engine over drive wheels is one part of the advantage.

5) 4WD, limited slip rear differential. This is one step better as the torque will be shared between both back tires should one lose traction. The torque transfer is not equal but anything is better than one tire spinning per axle.

6) 4WD, locking rear differential. Both back tires have equal torque along with at least one front tire getting torque. Big improvement in off road ability and a very popular feature used by may companies. All 4WD Off Road TRD Tacomas have this.

7) 4WD, limited slip front and rear differential (TRAC in H4). A big improvement in that torque is shared across both axles. All 2009+ 4WD Tacomas have this.

8) 4WD Active Traction Control (A-TRAC). The ultimate stock traction system equiped on 2009+ 4WD Off Road TRD Tacomas. Provides the traction of front and rear lockers while in low range (L4) by automatically matching a non-traction tire's rotation speed to the opposite traction tire, when there is a difference. Steering control is not affected making A-TRAC superior for trail driving. The rear locking differential is also on the same model trucks should one wish to use it or both together. The A-TRAC will only be active with the rear locked up to 3 mph. A-TRAC used alone has no speed restriction.

9) 4WD with aftermarket front locker (and factory stock or aftermarket rear locker). For the true hard-core off roaders as nothing to them can beat front and rear lockers. Both wheels on each axle are gear-locked together for smooth equal torque to each tire. Steering is very difficult, so use of lockers is limited.

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The above is my understanding and experience with 4WD, and I tried to base it on the facts as I know them.

I hope it helps some with understanding how traction systems work, and how well Toyota has done at creating traction vehicles.

Toyota literature does fall short on explaining the traction workings, so I am inspired to write guides here on TW to our truck features, specially when off road!

(I did try to do more compromising with my friends with front lockers and Sport TRDs in my writing... Merry Christmas & Happy Festivus!)

 

very easy to understand write up... Good job and thx

 

Thanks for the nice words Jason! Merry Christmas!

 

x2 , Nice David

Merry Ho Ho

 

Wow, great write up with good info. And very easy to read and understand.

 

When I raced Nitro Powered RC trucks, I learned a lot about diff operation. So many variables to make so many differences.

It would be cool if Toyota put a lockable diff in the transfer case. Then you could have AWD for every day driving in not so ideal conditions, and 4WD with it locked. Probably just one more thing to go wrong tho....

 

Yup, 4Runner, Land Crusier, etc.

The truck does fine in rear wheel drive most of the time... and shift-on-the-fly makes using 4WD a sinch when ever you need the front drive too.

Full time 4WD (AWD) would really not help the trucks weak gas mileage numbers, so I don't mind if they don't offer it. The A-TRAC alone is such a blessing, it gives the Tacoma everything needed to go everywhere with confidence and security.

 

Not really Land Cruisers had that for long time and each will probably outlast any Tacoma TC.
They are also extremely fun to drive and handle snow, and ice super well. Before any traction control LC (ultimate offroad vehicle) would come with AWD + Limited slip in center diff and F/R lockers.
BTW Sequioa comes with even better setup (only some) 2wd - AWD - 4H - 4L

 

David......Cool writeup. So if I understand this right, I have a 06 TRD sport, prerunner. I have limited slip (LSD) correct? SO if one of my rear tires get stuck, it will automatically shift torque over to the other tire to help me get unstuck? Thanks for the info.

 

There will be a sticker on the differential that alerts you to use a special gear oil for the LSD.

It is probably better to say that when one of your rear tires starts to spin more because it in the air, on ice, in mud, etc., the LSD will SLOW down that spinning which transfers that energy to the traction tire, giving it enough torque to roll you ahead.

The newer Tacos use the brakes to slow down the spinning (TRAC).

 

Yep, I checked it out to see if I had the sticker. I indeed do have the LSD. Thanks for explaining. I just wished I had done a bit more research before buying my truck. I would have gotten a 4x4 or OR.

 

I hear that a lot from Sport owners... That's why I do my best to explain that if you want maximum ability, get the Off Road 4WD.

If you are a 'street driver' mostly and want to sport car look with your truck, then they have the Sport model... If you do a little off roading and snow driving, the Sport will be fine... It is a Toyota afterall!

The A-TRAC and Locker really do make the truck cover foul terrain like an army tank... so if you have the off pavement urge, do get the Off Road 4WD... As they say, it is better to have it and not need it, than to need it and not have it.

Nobody has EVER pulled me out of a stuck, ever! I don't have a winch either... 4WD + Traction Control & A-TRAC + lower air pressure in sand, all make the truck unstoppable!

 

Everything on the Internet message boards is for entertainment as well as education... so my posts are intended to combine the two.

While I have no beef with Sport owners (in fact a feel their pain when they learn they were short-changed in the traction department), I do think Toyota should either put A-TRAC in all TRDs or do a better job at informing potential buyers of the differences between a Sport and an Off Road TRD.

As for the other stuff, I am doing so to add some comic relief. I have no problem deleting the exchange between us that is beyond the technical converstaion.

Thanks for writing... I promiss to not be a hoser, okay, 'eh?

 

Agreed

 

Part of having traction is knowing how to get it...

 

Pretty interesting write-up as always. Thumbs-up.

 

Thanks Supra!

 

Does this apply to 2WD TRD Sport Models as well? What if you do NO off roading and are only concerened about occasional snow/ice (living in the south).

I'm wondering if Toyota's newer traction control features have reduced the need for 4WD for folks who only need 4WD as "insurance" against really bad weather.

I'm hoping Auto LSD will good enough for me.

 

Obviously it is an advantage to not just be stuck when one tire is on ice or mush and the other is on firm ground.

Open differentials will allow the free and easy tire to spin... if only the power was on that other tire!!!

By limiting the slip (slowing the spinning tire) more energy would transfer to the other tire... and it may be enough to move you ahead.

Limiting the slip can come from inside the differential with clutches or from a traction control that uses the wheel's brake to slow it down.

A locking differential will divide the power equally so the spinning tire and traction tire both rotate the same. A-TRAC also does this with brakes but only as long as it is needed to move ahead ('automatic lockers') so steering isn't affected.

So, yes a 2WD vehicle will be more able to cope with getting unstuck if it has traction control, a limited slip differential or a locking differential.

The '09+ Tacomas all have TRAC in 2WD (light limited slip, brakes + engine regulation) and AUTO LSD (stronger limited slip, no engine regulation).

All Tacomas since '09 have at least these three drive modes:
1) TRAC is the normal mode.
2) Push the VSC switch once for AUTO LSD (also called TRAC OFF).
3) Stop moving and hold down the VSC switch for 3+ seconds for no traction control/ open differential (also called VSC OFF).

 

I might just start a new thread for this... but let's see how it looks here, first!

Recently some have posted that the truck was 'stuck' in '4WD' because the light was on or blinking... only to later learn it was just the differential lock switch pushed in! That light is below the 4WD light...

The lights are different... So, I just took some photos so we all can see. Let's go through the levels of traction activation and see what it all looks like:



Normal dial position for paved roads or where traction assistance of 4WD (four wheel drive) is not needed.



The lower switch, next to mirror controls (car with skid lines below) is the VSC OFF switch. This also activates AUTO LSD when in 2WD with a quick push. Auto LSD is traction control without the engine output regulated.



This is what comes on with AUTO LSD active. The VSC OFF light goes out above 30 mph.



If you stop the truck and hold down the VSC OFF switch for 3+ seconds, VSC and TRAC both turn off for open differential(s) in H2 or H4.



Go into H4 (4WD High Range) from 0-60 mph if you need more traction because of poor conditions or off highway needs.



This is the 4WD High Range indicator light... two differentials and 4 tires. TRAC in H4 has no engine regulation, the same as AUTO LSD in H2.



For more torque to power through deep snow or mud or to climb up or down steep grades, stop truck, put tranny into N (Neutral, not Park), and rotate dial to L4.



Low Range 4WD indicator light. VSC goes off in L4 and both differentails are open.



If your 4WD Tacoma is an '09 + Off Road TRD, you have 'Active Traction Control' (A-TRAC) that provides the 'brake-locking' of any non-traction (spinning) tires front or rear for tractor like crawling/ climbing. Gives traction control while in low range. Push this switch just once when in L4 and A-TRAC will activate when-ever needed to keep moving while in L4.



A-TRAC activated light.

REAR LOCKER:



As Toyota states, use only as a last resort and turn off when out of trouble.



While in L4 (for 4WD Tacomas), press the RR DIFF LOCK switch. (I engaged it twice today while stopped)



The Rear Differential Lock indicator is the x'ed rear differential image. If it doesn't engage, or if it is pressed while in H4 or H2 (for 4WD Tacomas) it will BLINK! Remember, when locked there is no differential action to allow the tires to rotate at different speeds, as needed when turning.