How to check and add fluid to your automatic transmission, Find the automatic transmission fluid pipe. on many newer cars, the transmission fluid pipe will be labeled; if not, consult your owner's manual for its location.. How to check transmission and discover possible, First, check the transmission fluid level and condition. if you don't know how to do it, here is an illustration: how to check the automatic fluid. Video: how to check transmission fluid levels, Video: how to check transmission fluid levels with matt ediger. it's important to routinely check the transmission fluid levels in your car, but don't.