A.D.D. and 4WD

[repo]

I bought a 1999 SR5 4WD v6 Automatic last week (BTW thanks for the buying advice I got here). Got some more newb questions sorry...

I'm learning about the 4WD system before I use it this winter. I don't have a side button on the front control lever, and I don't have any extra switches on the console. The manual mentions ADD and center diff and rear diff. I beleive I don't have rear diff lock because there is no switch for it.

The '99 SR5 does NOT have "Center Differential" but the Limited does, correct?

How can I tell if I have A.D.D. on this vehicle?

Is there a general FAQ for using the 4runner's 4WD system (like what situations to use it in)? Is it OK to use 4H on dirt/gravel roads? the back end slides around a fair bit on gravel roads but I suppose tires could also be a factor.

EDIT: forget to say, it's the v6 engine.

 

[RonMAIDEN]

Yep,only the Limited's mutli-mode auto has the AWD with center diff lock. My mom has a '99 Limited and it is a nice feature in the slush and ice but I still do ok with mine.

The pre '01 SR5s had standard 4wd and it's ok to drive in 4hi on dirt or gravel but you should only use it when you really need it to reduce wear and tear.
There should be a sticker on one of your visors outlining the 4wd system.