2009 VSC/TRAC/AUTO-LSD snow test

Yup

I think VSC is fully active. Sometimes I want to do an ass sliding U-Turn, or whatever. ALSD as it is set up currently, still has VSC, just no throttle intervention till around 30 mph. Maybe if VSC shut off up to 30 mph, that would be best.

Often I am pulling out onto an icy / slippery highway and the VSC buzzer sounds, because the tires are spinning, which makes the truck think I am skidding (vehicle speed X steering angle = calculated amount of Yaw). When in fact I'm just spinning wheels to get moving.

Donuts actually work better with LSD anyhow, lol. But that is my point, there is a time when VSC is not needed, but there is virtually never a good time for open diffs, so this mode is nearly pointless.

That's an interesting point, brake booster failure is incredibly uncommon, however.
Any they should get rid of the warning buzzer.....

 

Sorry for the revive, but I figured it had to be better than starting a new thread for this one question I have. I am not asking the question because I am lazy and dont want to look, I have spent the past month or more and read virtually every thread on these systems but still have this one basic question.

For "redneck activities" i.e. mudding. In a virtually no traction situation, what 4WD mode would I need to use? I have always practiced with my Jeep just give it plenty of throttle keeping forward momentum, and keep the tires spinning. With these advanced features I am just unsure as to which would be best for this situation.


Would an open differential be best, so that all tires can keep moving ( to clean out the tire treads in hope of getting some grip). Or am I wrong in that line of thinking? From doing the reading, I am comfortable with which mode is best for sand, and rock, and I think I know what would be best for hill climb in loose gravel or slick surface. It is just this mudding situation I can't grasp. All help is appreciated!

 

For true mud, I'd start with 4Hi with all the traction doohickies off (open diffs) and keep the throttle revved to keep the lugs clear.

If it's a layer of mud over dirt or more clay like (i.e. a slick surface with something firm underneath) I'd start with 4Hi TRAC and go from there. Same goes for sand, gravel, basically anything but rock crawling.

 

I just did some deep mud, and I can say that with ATRAC off, I was instantly stuck, open diffs screwed me. At no point did I find that ATRAC was limiting my ability to spin the tires enough, lol.

 

I can see that...if both wheels were regularly spinning, I guess it wouldn't slow/stop either tire too much...

 

It only cycled on here and there, but just as I would be starting to get stuck, it would kick in, cycling like mad. The nice part was it only seemed to kick in when needed, not like it was cycling all the time.

 

Hi Shack,

Look at this video of the FJ using A-TRAC in 'sugar sand'... it is almost like mud in that ALL FOUR tires have EQUAL LOSS of traction, so ALL FOUR tires are receiving TORQUE from the engine. This is what I think you want to do, is have all four tires spinning you through the mud...? IF you were in open differential (VSC OFF/ TRAC OFF) Mode, then you would have one tire in front and one in the rear spinning.

Lockers became the rage to overcome this '4WD really is TWO wheels driving' issue... Toyota gave us a rear locker and others have added a front locker from ARB or ?.

Starting in 2009, Tacomas were available, with Active Traction Control (A-TRAC) which gives us the positives of front and rear lockers, without the negative stearing issues or added cost!

So, either TRAC in H4 or A-TRAC in L4 will give you the FOUR WHEEL DRIVE on all four wheels you seek! Here's that video (notice all 4 tires spinning, but the FJ never gets stuck):

http://www.youtube.com/watch?v=_VHxslTiQug&feature=player_embedded

 

Ok thank you all very much. Open differentials is not what I want under any of the driving circumstances I have mentioned. I only want open if for some reason I need to rock myself out of a situation a la old school 4 wheel drive. Awesome, I think I finally understand! Now, I just need to learn to ride rocky trails with my manual tranny and I will be all set.

 

I'm thinking of buying a Tacoma DC/LB. My concern is how it handles in the snow. I’m not sure if this is a good place to post or not but it seemed appropriate because of all the talk about VSC, LSD, TRAC and A-TRAC.

Some background: I've had a Jeep Cherokee, two Yukon’s and two Subaru Outback Sedans. Believe it or not the Subaru was/is the best in the snow and I never got stuck...even through some pretty bad snow storms. I’ve gone through snow I never imagined I’d get through with the Subaru and I’ve had the Cherokee and Yukon’s stuck in snow that you would have thought they could handle easy. I’ve never really understood that. Some of it has to do with getting power/traction to the wheels that need it I think. Seems like in the Cherokee and Yukon I’d have only one front and one back spinning when I’d get stuck. Keep in mind I don't claim to have exceptional or above average driving skills...just a basic driver with experience in snow and ice.

I’m concerned about not having full time 4 wheel drive. I was driving through KS once and kept hitting patches of black ice in my Yukon and before I'd know it by back end was sliding out. Most of the road was dry so I could not drive in 4x4. After that trip I told myself I’d never get another vehicle that didn’t have full time 4 wheel drive. But now I’m considering the Tacoma.

Will the VSC help to keep the back end from sliding out at highway speeds and slower in snowing/icy conditions when in 2X4? If I’m driving down interstate and hit a slick spot will the VSR help keep me going straight and not let the back end slide out? Anyone have experience with this?

With LSD…Does the vehicle actual break the wheel without traction to transfer the power to the wheel with traction? Would this help keep me from getting stuck in snow where only one front and back wheel turns or do I need the locker for that. (Which I can’t get on a Sport) I think that may be why the Subaru does so well in the snow…it gets power to the wheel that needs it.

What is TRAC/A-TRAC? Am I correct in thinking that the TRAC system is only available in the Off-Road models and is designed for more aggressive off road?

 

Full time 4x4 sucks. That's not based on facts or testing, that's personal bias, and that always matters the most.

Yes, that is exactly it's purpose. Now, it's a vehicle and not a miracle worker. If you're going 70 in snowy conditions and hit slick road, the ass end may go. But that's your fault for driving too fast for the conditions. No amount of VSC/traction control will save your ass there.

You asked the same question twice.

Auto-LSD will perform that function for the rear 2 wheels in 4x2, yes, and yes, it's managed through the ABS system.

For kicking ass in snow, sand, etc., you want TRAC/A-TRAC.

The reason you have two wheels spinning when in snow is because you have open differentials.

TRAC is in all 09+ Tacomas. It is a traction control system wherein when one wheel begins to spin, the truck brakes the spinning wheel, forcing power to the non-spinning wheel.

A-TRAC is a more aggressive version of this that essentially functions like front and rear locking differentials, but without the steering problems the lockers cause. A-TRAC is only available on 09+ 4x4 TRD OffRoad Tacomas.

If you have an A-TRAC equipped Tacoma, you have a very big gun for offroad conditions, snow or otherwise.

 

Welcome to Tacoma World!

The Long Bed is not available with the Off Road TRD package, sadly. So, no A-TRAC system (which gives you the traction of front and rear lockers). However, you will have TRAC, VSC, AUTO LSD and can do the Yellow Wire Mod to get TRAC to work in L4 (low range 4WD) which otherwise has only an open differential.

Yes, the AUTO LSD (no engine output regulation, just braking) works well in 2WD to get you going then turn it off and then let TRAC (has output regulation) keep you going.

In 4WD High, the TRAC is really the same as AUTO LSD, but on all 4 (no engine output regulation).

H4 (high range 4WD) with TRAC is highly capable and can be driven at or near hwy. speed. You are correct that the Bosch VSC system is designed to keep you going in the direction you are wishing to go (in H2 or H4).

See my link in my signature below for more details on the traction controls.

I am a former Subaru owner and know they are capable vehicles... Mine were 4WD and not AWD. The reason your AWD Subaru did so well is probably the limited slip front and rear of All Wheel Drive... Your Tacoma in H4 will do as well, but being that there is no center differential it is not designed for dry pavement, so let the VSC keep you on track then. Wet or snowy paved roads and all dirt roads, up to 60 MPH, put it in H4

 

That's a big help. I didn't realize that all 09+ had the TRAC systems. It sure seems to be a nice truck and rides well. Thanks again for the feedback!

 

If you have the button that is a truck with wavey lines below, then you have TRAC and AUTO LSD and VSC. If it was an Off Road TRD, then you would have the A-TRAC and hydraulic brake booster (makes the TRAC and AUTO LSD work better, as well). None-the-less, you still have a good truck and the limited slip system will enhance your four wheeling experience. Do a search for the YELLOW WIRE mod. and you can have the TRAC work in L4, as well.

Here is what the '09+ 4WD Tacomas have:

1) 2WD: VSC and TRAC active, engine regulated ('Limited Slip Lite').
2) 2WD: 'AUTO LSD' ('TRAC OFF MODE'). No engine regulation for 'strong' limited slip.
3) 2WD: 'VSC OFF MODE' (TRAC is off for 'open differential').
4) 4WD-Hi: VSC and TRAC active. No engine regulation for 'strong' limited slip.
5) 4WD-Hi: 'VSC OFF MODE' (TRAC is off for 'open differentials').
6) 4WD-Lo: VSC and TRAC are both off in L4 ('open differentials').
(plus some models have the rear locker, #8 below)

Now, if you get an OFF ROAD TRD, you also get:

7) 4WD-Lo: 'A-TRAC' on gives a 'locker-like, super strong' limited slip, front and rear.
8) 4WD-Lo: Rear Differential Locked and open front differential (A-TRAC off).
9) 4WD-Lo: RR DIFF LOCK + A-TRAC on, 3 MPH limit.

 

It sure did for me this past winter. I was expecting a lot of trouble from a lightly-loaded RWD truck in winter, and I had basically zero problems. VSC saved my ass on a downhill exit ramp that I took to avoid a sudden pileup. The ramp was icy and curved, and there was a stop sign at the end; I expected to spin and/or slide right through the stop sign, but VSC activated during the turn, and then the ABS stopped me before the sign.

Yep. Regular traction control (default mode) will reduce engine power and brake the wheel with less traction.

Turning off TRAC turns on ALSD (in my 2wd truck, and I presume in a 4wd truck that is still in 2-Hi). That works just like TRAC, but it does not reduce engine power--it only uses the brakes.

Both worked great last winter.

Look for the member's signature with the mode explanations. That does a better job than I could do here.

 

That was me... I changed my sig. as the 9 drive modes sig. was around for a long time and the traction control questions have mostly ended. I did post the 9 drive modes above, and they are still in my post on the traction systems (link below).

 

Resurrecting an old thread...

So if RR Locker + A-trac is a 3 mph limit, it would seem you may prefer just 4lo + Atrac for most tough situations that arent an actual crawl.

Is it 3mph wheel speed or truck speed?