hey...im new to jeeps (getting ready to buy my first). im definitely getting a 4.0 but i noticed one that i was looking at recently had a 3 speed automatic. my biggest concern is what kind of rpm's am i gonna be running at 70 mph? and will it have any bearing on the power output? do they make a 4 speed automatic or just the 3 speed? as far as the year model, im looking at 97-02. thanks a lot.