My 2006 Sequoia attempts to go into 4 wheel hi, but grinds and then goes back to 2 hi. Any ideas?

Question edited for clarity.
Question moved to model category.

2006 Toyota tundra 4.7L Front End Torque Specs

toyota-specs.com https://toyota-specs.com > cars > 2006 > tundra4.7 > t...
Toyota Tundra Front Axle Nut Torque Spec : 203 ft-lbs · Toyota Tundra Wheel Hub Torque Spec : 100 ft-lbs ...

BHA53102 Axle / Spindle Nut Torque Specification

1A Auto https://docs.1aauto.com > BHA53102 Torque S... PDF Toyota. 4Runner. 1996-02 4 Wheel Drive. Front. 174. 236. Toyota. Sequoia ... Tacoma. 2001-04 4 Wheel Drive. Front. 173. 235. Toyota. Tundra. 2000-06 4 Wheel ...
1 page
https://www.google.com/search?q=2006+Toyota+Tundra+4x4+front+axle+torque

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You need a new , rebuilt, or most likely, a junk yard transfer case. Your lucky that 2 wheel drive still works..

Try toyotas owners website. maybe someone can answer it there.

Switch may be bad. Change switch should fix it.

I'd bet your brake rotors are grooved and need to be resurfaced (or replaced if they are too thin). This also means you should replace the pads too.

sounds like you need an encoder motor sensor and an pcm recalibration

there are 2 systems.
one is a part time system only.the 4x4 locks and is for ice mud and snow.Driving full time will damage the transfer case.The other system is a full time system and the selector says 2wd,4wd part time ,4wd full time and 4 lo. if in full time,it can be driven all the time even on dry roads.The full time is really an all wheel drive system.
the 4low is a very low gear and the main shifter has to be put in neutral and then the transfer case put in 4 low.attempting to put it in 4 low while in "drive" will make a gear grinding noise.
getting out of 4 low is the opposite.shifter to neutral and then put it in 2wd and then in drive.The newer durango has an electronic transfer case with a dial on the dash.The 2002 was available with 2wd,4wd,awd and 4 lo on a switch.The 1999 has the lever on the floor .

If you are in 4 low to go back to 2 wheel drive you have to be in neutral if you aren't already

You need to have the wheel speed sensors checked. If one is not reading the proper rPM of the wheels, it thinks that the other wheel is spinning, and the TRAC applies the brakes on that side.
A good tech with a good scan tool might be able to read the sensors, but, a Toyota tech is your best bet.

THIS IS 2 LITTLE PLASTIC TABS ON THE FORK IN THE TRANSFER CASE.