Trans shifting back and fourth

my 04 ram 1500 4.7, when I get up to 50 and 60 4th to 5th gear wants to jump back in fourth every few seconds it does this in 2nd and 3rd to. Not constantly but it will drive fine then all the sudden drop to a lower gear or jump to a higher gear. Tried changing strainer and filter with new fluids today, it did not help at all any ideas?