I'm still not sure what you're saying.....
I said - If you buy a 4WD truck and NEVER engage the 4WD system for 5 or even 10 years..... will it still work?
And I'm saying - I doubt it will.
That's why the manual specifically recommends that you engage it atleast once a month.
If you can use 4 lo in all gears, then can you use 4 hi in all gears as well? If so, then what exactlly is the difference between 4 lo and 4 hi?
Does 4 lo limit the maximum speed you can go in each gear vs 4 hi or 2 hi?
My grandfather had a old trail 90 Honda bike and it had a selector switch on the transmission. Selector switch set to low, the bike would go about half as fast in each gear, compaired to it being set to hi.
Guessing the Tacoma works in the same kind of way?