Toyota Factory locker on 88 4Runner?

[Doncolberto530]

Hey fellow 4Runner people, I recently bought an 88 4Runner V6 and have been loving it besides the mpg's... Anyways while looking over the owners manual I noticed a note that was hand written on the cover along with some other maintenance notes saying: March 1989-Toyota Rear locker installed.... So short of cracking open the rear end what could this be referring to? I know Toyota has lockers on some of the newer stuff but have not been able to find any info on what they had available back then. So what do you all think?

 

[fourwd1]

There was no factory locker option in the 80's.
The PO may have retrofitted a later Toyota e-locker, and if so the control motor and wiring would be obvious. Otherwise he may have had any aftermarket locker installed.