My computer has been telling me that I needed to flush the transmission well I have not done that yet and I think it's 900 miles over the limit all of a sudden this morning when I decelerate it revs up and then it'll drop back down when I pull over and cut the car off and let it rest for a while it'll be okay to drive again for like 20 more minutes and then I have to do the same thing let It rest now it's like stuck in second gear and I can't force it over 3 RPMs cuz I'm scared it's going to blow something up somebody please help me