Okay, on a manual or automatic. The manual does not have one. It is a square plug on the side of the tranny. You have to remove it, put your finger inside and it should touch fluid. If not, refill it with the proper tranny fluid. The automatic, is low behind the transverse engine by the firewall, in some models. Acura also manufactured a sealed unit that must be flushed at the dealership and does not offer servicable part to backyard mechanics. Some of the newer vehicles (impala) also have this tranny. Pain in the butt.