I just purchased this car, its auto, i knew before i bought the car that 4th gear slips and i would simply put it into D2 and it'll bypass the 4th slipping. However i got home after buying the car i tried putting it in reverse and it wouldn't work, i let the car sat for 30- an hour and tried it again and it works fine. Whenever the car is warm the 4th gear slips and the reverse won't work. There's no check engine light, and i was thinking about flushing the fluid. Anyone opinion would be great, thanks.

 

Do three drain-refill cycles with Honda ATF and then go from there.