This depends somewhat on what country you are in, but for US, it’s basically as follows:
Gen 1: not sure, through 1990
Gen 2: 91-97
Gen 2.5: 98-2000 (2000 is not quite the same, called Endeavor sometimes, and has no locker option)
Gen 3: 2001-2002
Gen 3.5: 2003-2006 (larger 3.8L motor)