Open as far as I know and the traction contol manages wheel slippage.

 

I also got the answer from "Toyota Brand Engagement Center" copied here:
"...We have researched your inquiry and determined the front and rear diff is limited-slip. You can find additional details about this information in your 2020 Sequoia Owner's Manual starting on page 320..."

However, I refer to the page 320, it's about AUTO LSD system. I'm still confused the answer from Toyota Center. Any comments?

 

As @[B]remember5[/B] indicated, the Sequoia uses computer controlled braking to handle wheel slippage. The Sequoia, at least to my knowledge, does not have a mechanically operated LSD and the differentials are completely open. So no true LSD in the mechanical sense, but I would venture to say that the Auto LSD function (computer controlled) is more than sufficient for all but the most serious off-roaders.

 

I agree with meder, there is no such thing as a true limited slip differential in the front. If there was you would slide through turns and your front tires would wear out prematurely. There are front locking differentials which are essentially open until locked. Example is the G Wagen, first choice is center lock to bring the front and rear axles together. Second choice is rear diff to lock the center and rear. Third and last choice is to lock the front diff. This is of course related to "on road" vehicles. Woods buggies often weld the axle gears to create a locked diff front and rear but driveability on the road is nill.

 

Isn't it in the name?

Torsen limited slip

 

the Sequoia 4x4 has 3 differentials: Torsen limited-slip center diff with lock, front diff, rear diff.
Thanks a lot for all inputs! According to our discussion and to my knowledge so far, the front and rear diff is mechanically open. Regarding to the front/rear diff, however, Sequoia comes with so called "AUTO LSD system", that uses individual brake inputs to control wheel spin in off-road situation, the manual page 320 lists how to active/deactive.

 

Toyota AUTO LSD system can be used on 2WD mode only, as the manual mentions. It CANNOT be used on 4HI, 4LO modes, as I tested.

 

IMHO and experience--and generally speaking--when things become a 'smidge more than mild, level ground off-roading, electronic ABS style braking systems used to simulate differentials (which they almost never do with some rare brand exceptions) are far too slow to be effective ONCE MOMENTUM IS LOST (this is especially true with "street" tires).
The below is an example, which eventually works but it illustrates what I mean:

Advance to 14:33

Proper mechanical or nearly instant Electronic Limited Slip differentials (meaning the rear dif senses slippage and applies power almost instantly to both axles) are generally better off-road than a computer sensing slippage, making triple sure you aren't going to sue the vehicle manufacturer, then applying brake pressure to the spinning wheel to send power to the non spinning wheel (the video above).

Nothing beats a rear locker except both a front and rear locker (assuming center diff is locked).

All of this advantage changes when on ice/snowy slippery roads as with all wheels spinning you now lost nearly all contact with the road (watch the videos of RWD guys--even in the dry--spinning their tires and someone is able to pushing the entire rear end around (video below). They can only do that b/c both wheels have no traction. If only one wheel was spinning, they could not do that).