I have a 2004 LS V6. First few days of owning it shifted fine now the shifts are a little hard When selecting gear. I've read many posts on here saying there is no area technically fill it. I have to do it from underneath. I wonder if anybody has a link or knows the step by step to this fluid changing process. I know it's pretty simple but I've never done one this way. I guess my main concern is how do I know if it's low when I begin and how do I know it's full when I'm done thanks for any