One of our readers just did a writeup on that, here it is:
http://www.4x4wire.com/toyota/minutemods/greywire_mod/

The locker should be engaged below 5 mph. Once locked, it's ok to go faster. With stock (or near stock) size tires the locker is pretty strong.


Wheeling a Stepside Tacoma on 37s
Exploring in a T4R Ltd V8