No Worries, it'll work fine with the 80/90 and the additive. The additive is really just to stop the thing from groaning and grabbing during normal driving conditions. You can run just the 80/90 in it without the additive, and if it were strictly off road, probably be fine, but on road, i'd imagine you can wear the friction discs out quicker without the additive. <img src="/forums/images/graemlins/patriot.gif" alt="" />

-Todd
1987 Montero 2.6l 5-speed (Sold...but I still miss her)
2008 Jeep Patriot Sport 4x4