The.PWR and 2nd buttons I'm sure are covered in the owners manual. My 2nd gen Sequoia shows Limited slip on the dash. To my knowledge it has a Torsen in the transfer case and TRAC on the disc brakes. I'm still not sure what the limited slip is. It's a 4WD but all my vehicles are Toyota 4WDs. So it doesn't see anything but a few dirt roads.
This is the same transmission I have in my 80 and the PWR button is very useful for towing. For quite a bit of us, we use that button just so we can move our heavy pigs around with some semblance of authority! I'd hit that PWR button while towing for better shifting. You might leave it in that mode always because I think you'll like the way the engine/transmission work in that mode.
