The transmission dipstick, which is where you will also add fluid, is on the right side of the engine. Between the dist. and the rad. down on the transmission. In all my experience with Honda transmissions I would NOT suggest pouring the treatment into the transmission! Honda transmissions do not take to kindly to other fluids poured in them which is why you can only use Honda fluid (dextron 3). When other fluid is put into the transmission it can cause problem to occur. If you are having a problem with your transmission and that is why you want to use the treatment then the treatment is not going to help. If you are using it because you think that it will help to prevent anything to happen then you are actually going to cause problems.The best thing for you to do is just change the fluid every 15k miles. *I have seen cases that if you catch a bad transmission in the VERY early stages of a failing transmission that if you change the fluid every time to every other oil change then it can help your transmission.