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

Im busy this weeking but maybe next weekend. There are a lot of videos on youtube and a few almost crash. Type in trucks at hollister hill.

 

When (if) this gets done, be sure to be aggressive when using A-TRAC. What I mean is if you come to a rock or log, do give it the gas to climb up. Some may be used to wheel spin on the one tire (open diff) when the traction tire stops moving. A-TRAC (and TRAC in H4 to a lesser degree) matches tire rotation, so that loose tire won't spin like it did before A-TRAC. Give it the gas, and make the truck climb up the rock... I call that 'waking-up' the A-TRAC.

A former TW member video recorded the front tire of his Tacoma at the base of a rock, gave it a couple of bumps, and then posted A-TRAC didn't work. My truck acts like an army tank with the A-TRAC, it climbs anything I put in front of it if there is any traction to be had.

It is simple: 4 tires that pull the truck beats just two (one in the front and one in the back). A-TRAC (like lockers) makes all the tires productive to move you. TRAC without engine regulation (AUTO LSD/ TRAC OFF MODE) is a limited slip that shares power to all tires, but not as equally as A-TRAC or lockers, so there is some spin on the loose tires, just not as much as with no traction control.

 

I just wanted to post this quick reference card (as an attachment) that I made to keep track of all of my truck's traction options. If you print it on card stock, cut it out, and laminate it, it will fit perfectly in the little pouch on the driver's side sun visor. It begins by listing three options for L4 driving. The first one adds back some automation, while the other two deal with locking the differential and Downhill Assist Control. The remaining four options are the different modes for the VSC OFF switch. I used the info from the owners's manual to create this and keep it handy for when I am in a bind and need answers regarding the truck's capability. I hope that it may help others with the TRD Off Road package and automatic transmissions in experimenting with the options without holding a book in their hands.

I welcome any comments and/or editing suggestions.

See my full build here:
http://www.tacomaworld.com/forum/new-members/308438-new-colorado-tacoma-owner.html

 

That is awesome. Thanks for sharing.

 

Here is a less wordy chart, that included the changes made in 2012:

http://www.tacomaworld.com/forum/2n...raction-controls-2009-2014-a.html#post8000440

 

Thanks for the informative thread, this is exactly what I was looking for.

 

Happy to help!

 

Just curious, what are your experiences with the YWM in snow? I did the YWM yesterday and took it out to try in the snow. Four different times I tried starting in VERY limited traction situations and it did NOT get me out. Two times in 8-10" all 4 just dug myself deeper, then had to shovel my way out. Then twice on hard snow packed/icy hills. I would stop in the middle of the hill try to start from a stop. I would either just sit and spin or wheels would spin while I would slide backwards.

I am pretty sure that I did the YWM correctly. When I was stuck in deep snow, the 4Lo light would blink, and I would watch the left rear tire spin, then stop and I could hear the right rear spin and it would go back and forth.

Now, I am assuming my BFG AT's with 4/32's tread left didn't help the situation. I am long overdue for new tires. But that is a subject for another thread.

So, two questions:
1. What are your experiences in snow, either deep or hard packed?
2. I am assuming I did it correct (I have limited mechanical experience)? Since in 4lo I saw the tire spin alternating from side to side. In the past, while I was in 4lo the tires would just spin.

Just for the record. Disconnected battery. Pulled out first white clip of wires. I cut the second yellow wire (with the thin black line), and installed a switch that I attached to the inside of the glove box. My truck is 5+ years old and paid off so I am not worried about dealer and warranty. When I switch it off, the 4lo goes solid and tire just spins.

Just letting you know. I posted these questions in a few threads, not sure where I would get answers.

 

If you are asking me, I can't help since I have an Off Road TRD and A-TRAC.

L4 is normally open diffs, and that means one tire in front and one tire in the rear will spin freely once they are on a traction-less surface. A-TRAC and lockers matches tire rotation across the axles so all tires rotate equally.

Doing the yellow wire (4 Lo Trac) mod provides traction control in L4 to allow power to transfer to tires that have traction and not just to those without traction.

In deep snow (keep in mind where I live, there isn't any but I have driven to it), I have found that the rear locker + A-TRAC made driving a breeze off road. With the rear locked, the A-TRAC only works the front tires and then only when you drop to less than 3 mph... so only if you are nearly stuck... then it comes on and keeps you going!

 

I bought the new over 5 years ago and I NEVER thought I would use it like I do. I absolutely love the truck, and regret not getting an off road.

When I get my next truck (in about 4 years) I know EXACTLY what to look for.

 

I used exactly that combo to get up a steep hill in deep snow this weekend after high centering and getting stuck. Worked like a charm.

By the way, I re-read this post a few weeks ago and finally understand what you gain from hitting the auto LSD button. It is great when starting on a little snow or ice where you really don't need or want to kick it into 4wd. We have had tons of snow in the east this year and I have really appreciated the Off Road TRD package.

T

 

Sounds like you got it...

2WD: To improve traction, use AUTO LSD
4WD-LO: " , use A-TRAC

 

Great post but still a little confused. I own a 2014 TRD Sport 4x4. I only have the VSC off button (the truck with curvy lines). All I want to know is what to use for the following scenarios:

1. Driving on a snowy/icy road.

2. Getting stuck in the snow.

That's really the only reason why I have a truck. Thanks in advanced for your help.

 

The short answers....

1. 4H

2. 4H (plus generous amount of skinny pedal)



The VSC button is MOSTLY useless with 4x4 models. When in 2H one quick push of the button will give you a little bit stronger LSD effect, and if you are lacking THAT much traction you may as well go into 4H. There may be times when you will need to hold the button in and disable everything to get wheel spin up in 4H but when you do you will lose TRAC.

 

I think I have the same set up on my 09. 4x4 with the button to shut off VSC. Typically I do not use it. If I start to slip/spin I back off the gas a bit and it bites again. Or I go into 4H and just just drive. I've played around it with a bit and found I can just ignore that it is there and drive like I would any pick up.

 

In 2012, they changed H4 so that the standard mode has engine regulated TRAC. I would suggest a quick push of the VSC button to activate TRAC-OFF so you will have stronger TRAC without the regulation (just like you do for 2WD to have more TRAC).
Before 2012, the standard TRAC in H4 was unregulated... no quick button push.

 

2009-2011 Tacomas have 2 H4 modes: H4 (TRAC without regulation) and H4 (VSC OFF/ no traction control)

 

Correct, only the OFF ROAD TRD 4WD has more traction choices (Rear Locking Differential and A-TRAC).

1. H4, quick press of button (TRAC OFF), unless you are talking thin snow for safety, then the normal H4 no button press.

2. L4 for more torque/ power (no traction control so tires will spin). Turn your tires left and right to grab fresh bites.

 

I think I'm gonna go tie myself off to a big ass tree and set up a couple of cameras to record how the wheels pull in the different drive modes. Just for illustration purposes.