What exactly happens between 4Hi and 4Lo

Legit question, trying to learn. When I change from 4Hi to 4Lo, what exactly is happening with the transmission mechanically?

Is there actually a different set of gears the truck uses in 4Lo? Or is it a computer chip that simply changes RPMs and shift points but the gears are all still the same?

 

4 Lo is a whole set of different gears in the transfer case. 4 Hi is a 1:1 ratio, a typical 4 Lo gearing is like 2.5:1,
Your shift controller changes those gears when you shift.
Purely mechanical

 

Recommended that you don’t go much faster than walking speed in 4LO.

 

Wow, I guess I use my truck in non-recommended ways like 99% of the time I am in 4-low.

I've been offroading for about 20 years now, driving faster in 4low is totally fine, Just dont let the RPMs hang out to high for too long.

Oh, and on the 3.5 watch the oil pressure if you are at extreme angles

 

Detailed transfer case information:
https://www.youtube.com/embed/DlOm8_Tt81c