I am confused...your 4runner is 2002, right??
Rear locker was not available in 2002, nor 2001. I think the last year of the locker was 2000. In 2001 and up, Toyota incorporated 4-wheel traction control system on 4wd models and 2-wheel traction control on 2wd models. VSC (stability control) also became standard in 2001 and up.
The only time that you would have a rear locker on a 2002 if you/previous owner installed it after purchase. IN THEORY, this would work with the traction control, but i have heard ONLY 1 owner ever doing this.
Nice 4runner, BTW!