01 S60 2.4T transmission problems

[doughnut1122]

Hi everyone recently I bought a 2001 Volvo S60 2.4T I have the engine running great now but the only problem now is hesitant/slipping/hard shifting transmission problems when I got the car it had two transmission related codes I think one was P0180 and P1618 the transmission fluid does look gross and I'm sure it's never been changed so I'm going to do that also when you put it in drive it takes a few seconds to engage and go forward on its own also the same goes for reverse. If anybody has advice on the situation to figure out the problem I appreciate it thanks everyone.