Trac-off? What does it mean?

if you have auto trans in a TRD Off Road, if you turn Trac off , which you do when you turn Auto LSD on (2wd), does it just prevent throttle retardation? I mean Trac-on is just retarding throttle IF slip occurs in 2 wd? When engaging 4 wd it also turns Trac off. So the Trac-on status is just throttle retardation to prevent slip to start with and is only selectable with Auto LSD? If you depress the button for 3 secs, it turns off Trac, VSC and Sway control. If this explanation correct?

 

I gotta know, what is "throttle retardation?"

 

I thought TRAC-OFF turned off the Auto LSD

 

I think you are correct, it turns on Auto LSD. But in prior Generation Tacomas, there was ATRAC. I just wonder why Toyota calls it turning off TRAC, vs turning on Auto LSD. I believe IF left ON the throttle is reduced ( or retarded) to prevent spinning. In Owner's Manual it duscussed doing this when you need to spin and "rock" truck to get unstuck

 

ATRAC I thought was for 4Lo. And I'm not sure but I don't think TRAC adjusts the throttle, I believe it uses the brakes to limit the spinning tire

 

I wonder if the owners manual explains this?

 

Here is the deal.

Auto LSD is a fancy name for the "throttle retardation" you speak of. It is also known as "Traction Control" more commonly and exists on almost all cars made these days. Turning off TRAC turns off "Auto LSD" aka "Traction Control."

It turns off the Auto LSD when you go into 4wd because "Traction Control" is really designed to prevent excessive wheel spin on pavement at speed in say wet or slick conditions. It is not at all designed to improve traction offroad. In fact, it severely diminishes it. You WANT power offroad... cutting throttle offroad can be exactly what gets you stuck.

ATRAC on the other hand IS designed to be used offroad. It is similar to Auto LSD in some manors but operates completely different. ATRAC applies brakes to spinning wheels so that excess power is transferred to the wheel that has more traction. It does NOT cut power like Auto LSD does. ATRAC is a very nifty feature from Toyota that is not available on the average car. It effectively imitates lockers.

Edit: since the OP and many others probably have the auto I'll go a step further and note this. Manual transmission 3rd gen tacomas still come with ATRAC. The automatic transmission 3rd gen tacomas come with crawl control and multi-terrain select. The abilities of ATRAC are essentially bundled within the crawl control feature so it's not like the auto's don't have ATRAC anymore per se.

Edit2: I was wrong on a couple of things. See post #16 for my realizations after reading through the link posted in post #10 below.

 

https://www.tacomaworld.com/threads/a-trac-trac-auto-lsd-explained-easy-to-understand-i-hope.70551/
There you go.

 

Disregard missread

The part about reading the manual, meant that part

 

All good

 

TRAC = Auto LSD on/off (Tacoma uses a brake controlled system)
ATRAC = same thing as TRAC just for 4Lo
VSC = traction control on/off

I think you are thinking traction control and trac are the same but they are very different systems

 

My understanding in 4-hi pressing the button once for a second turns it off. This enables full engine power and allows an electronic LSD to engage. Holding it turns everything off. Is this correct?

My 2008 didn't have any of this fancy stuff.

 

trac and vsc are automatically engaged in 2H/4H/4L. not sure which disengages with short press or long press there should be icons that light up to tell you which systems are disengaged.

 

Thanks for the correction. I read through that link above and learned a few things.

First and foremost, like you said, Toyota's version of generic "Traction Control" which is found on all new cars is called VSC (vehicle stability control). This applies brakes and cuts power in the event the driver loses control of the vehicle.

Moving on to TRAC/Auto LSD, I didn't realize Toyota allows you to choose between two versions of it. One with throttle modulation and one without. Is nice, I like choice. And I admit I was wrong when I said the Auto LSD is a fancy term for their traction control. It is really more of a brake (and optionally throttle) actuated imitation of a true mechanical LSD found on sports cars. Also, given that TRAC/Auto LSD is a brake controlled system ATRAC is indeed the same, just more aggressive.

The nomenclatures make more sense now.

 

Oh my original statement was right! I thought your post looked funny and started to correct it but then decided I didn't have the energy for it lol

 

I'm learning stuff too lol. I guess "Auto LSD" is only used in 2wd. TRAC is used in 4H and ATRAC is used in 4L. All of them are similar where they use the brakes to control differential slipping. Does that sound right?

 

Auto LSD uses brakes only, and is only in 2wd. It is a strong "lsd" like feature.

TRAC in 2wd uses brakes and engine power regulation.

Trac in 4hi uses brakes but no longer uses engine regulation.

ATRAC is only in 4lo and only uses brakes. I believe it also applies to all 4 wheels. ATRAC can be used together with locking rear diff for super duper locker action (under 3mph)