I have a factory E-locker for sale for 1st gens. It came out of a 2001 4 Runner with only 67k on the clock when it was wrecked. It has a 4.10 ratio and can be swapped into an open diff with a little modification (there are several guides I found when trying to do the swap in my truck but it WILL NOT fit 5-lug trucks). It was known to be functioning when it was taken off the donor 4 Runner.
Asking $475 plus shipping. You can also come pick it up locally if you're in the KC area. PM with offers
Thanks for looking!