"New" 2007 MT6 FJ for the wife

Hi All - I just got my wife a 2007 FJ. She refuses to buy new and will ONLY drive manuals. She was in an Audi A4 Quattro (with 5 speed) so the thought of getting another AWD was reassuring. My question is about the transfer case. H, HL, and LL???? I read the manual and understand when Toyota wants one to use a particular 4 wheel drive mode, but as a long time 4 wheeler (owned several IH Scouts and Jeep CJ5s) and engineer, I would like a better definition of these modes. (i.e. what is the point of the “L”- does that mean LOCKED-IN?) I assume H is AWD with a center diff transferring power front/rear as necessary (like the Audi Q) and the others are with the center diff locked either with the transfer case in High or Low. Is that it in a nutshell? Also, are the front and rear diffs open, or are they limited slips? The wife’s does have the rear locker as well, but I don’t see her rock crawling any time soon in it.

BTW, my wife’s has TRD exaust, wheels nurf bars and skid plate – and she loves it more every day. We have not yet taken it off-road, but it seems to beg for the dirt as much as my old '94 4-Runner did.

Thanks,