pwb

Hi, i have a ZJ with AW4, but its seems better to ask the question here since ther are more XJ with AW4 than ZJ.
I dont know if this is a problem or it should be like this, but i think the torque converter seems a litle "slow". I know there are like to fans inside it and that the oil is the "glue" that binds the to fans togheter, my "problem" is that i think the fans dont "grip" as much that they should do.
The gear shift is good and fast, and the response in low speed in first gear is fine. But if i give gas when driving in let say 50km/h the rpm increase, but i dont think the speed increse as fast as it should. The gear shift from 2-3, 3-4, 3-4, 3-2 etc is fast and there isnt any slipping (slipping is when the gear shift takes to much time?).
I have changed the filter and oil, but the first filter i used didnt fit 100% so i used the car some miles (maybe 2 hour of driving) and then it behaved as it took time to get in reverse and it could shift down where it shoudnt shift down, but the shifting was back to normal after i replaced the filter (dont buy cheap filters). I think the torque response problem show up after after this, but im not sure, maybe im only got more used to the car and think its slower than before. I then drain and fill new oil (almost 4 liters). I think the oil has been a litle hot when i used it with the bad filter, the problem with the filter was that the litle round tube on the filter didnt fit correctly. Should i do another drain and refil of the oil, i know that not all the oil is replaced since i dont flush it.
If the oil has been hot, could that be the problem and that i need to do another or maybe two or more oil changes? I have used DexIII and my total oil change is 8 liters, 4 when i replaced to the bad filter and 4 when i replaced the filter again. Im not sure what oil the PO has used.