Transmission problem?

[YoYasu]

Hi, I've recently been having a problem with shifting gears in my 2.3 03 focus zx3. It's hard shifting down gears if the rpm drops around 4k+; it feels like the clutch is not pressed at all, that's how hard it is to change gear. I'll have to wait for the rpms to drop around 2k in the current gear, then downshift smoothly. It also does the same going up in gears, but usually just from 1st to 2nd(revving it high).
I just changed my external slave cylinder today, thinking that was the problem, but it's still the same for downshifting, though i don't really notice the roughness from going to 1st to 2nd anymore. Could it be time to change the transmission fluid, or is it just a bad tranny? In the 50k+ miles i've had the car, i've never changed the tranny fluid.
Thanks~

[Sponsor]

[zetecDon]

Moved to "General Technical Chat".