Tranny Slip

The automatic tranny in my 2.4 slips all the time. It has 76,000 miles on it. When you gun it from a dead stop the rpms rise more than normal and its killing my acceleration. And on highway driving @ about 70mph or any speed really when going up a hill it shifts down and then the rpms start rising slowly till i'm over the hill. I was thinking it was probally the clutches in the trans or the trans fluid is bad. I wasnt sure. Has anyone else had this problem? Thanks

[Oldsman]

i noticed some slipping once but had the fluid changed and it took care of it.

also i would say try adding a pint of fluid to the tranny first and see if that helps