Mazda Repair: shifting gears, shifting gears, trannys

Question
i was driving my 93mazda navajo last night and its got great acceleration but it feels like its remaining in one gear like i cant feel or hear it shifting at all, i only got up to 55mph and the rpm went to 4, do you recommend putting lucas transmission fix in it? is it normal not to feel orr hear the gear shifts?

Answer
it's normal not to feel shifting in automatic trannys if you have a high rpm when when driving that doesn't seem to change and only gets higher when your speed increases then it's a tranny problem if you put any additives in the tranny what you put in as of volume you also have to take out extra fluid only causes more damage