Car revvs up, not accelerating

2000 Cavalier 2.2L 4speed auto.
Bare with me please, I am in no way a mechanic.
Car idles fine. While driving the car will intermediately stop accelerating, even though it continues to rev if Im on the gas. Then all of a sudden it will shoot forward. Does this over and over. The "non-acceleration period" only lasts for a couple seconds.. then It drives fine for about a minute, then back to nothing.
My very limited mechanical knowledge tells me this is the tranny slipping but like I said I am not a mechanic.
I did notice that the speedo and odometer stop working during the periods on non-acceleration and the fluid does not smell burnt and is still a pinkish / red color.
Any thoughts are helpful..