I understand it was introduced starting with the '98 models. Is it an option for those models or was it on every single model from '98 and up? I want one without.

 

All 4WD Tahoe's have had Auto-Trac since 1998 except those equipped with AWD as an option in 2004.

The system works exactly the same as the old Insta-Trac system but offers an extra button with the "Auto" feature that you can ignore.