4 wheel drive question

[4.7Runner04]

Hey guys im new to the board... i just picked up an 04 sport edition v8. I was wondering if this thing is always in 4 wheel drive or if it just engauges when a wheel slips or something. it has no 2wd option on the switch, just 4high and 4low. Any help would be great. its sad because i was a Toyota tech for 4 years and dont know the answer to this question...

Thanks

 

[rook]

Hi Mike,
Welcome! The 4WD system is full time, using a Torsen center differential that is lockable. When open, the diff splits the torque front/rear as needed. There is a lot of info on the site. Search for ATRAC and check out some of the "sticky" posts for more info. Start here.