What causes trans. To slip

Thank you for your response , im trying to find out about this speed sensor i have been hearing about , the fluid was in good condition and the filter was very clean at the time of replacement ???

Speed sensors don't cause "slips". That's why I asked what is happening, specifically? A diagnostic tool is indispensable in being about to see data from components such as speed sensors.

Well , its my daughters car and upon asking more questions , it would seem it takes forever to shift , revs really high and hard shifts so it might not be a slipping , getting a 27 year old to give me specifics on what is going on is rather difficult . Lol

I understand. It might take a little first hand experience on your part to get some further clarity. Good luck.