When your transmission fluid filter has become clogged the most common symptom of the clogged transmission filter being clogged is a very high pitched whining noise that becomes worse when you put the transmission into reverse.
Also when your transmission fluid filter has become clogged or is becoming clogged your transmission may take longer than normal to shift up into gears especially when you're climbing hills.
To extend the life of your transmission you should get your transmission fluid and transmission filter replaced every 30,000 to 60,000 miles.
If your RPM's are going up but the vehicles speed isn't picking up then your transmission fluid filter is most likely clogged.