After driving about 30 miles the car acts like you are pressing the brakes and gas at the same time?

You can hear a moaning noise. Sometimes the brake pedal goes to the floor, and I have to pump the brakes. I have had the brakes, rotors, calipers and brake line replaced. I had been told by a transmission shop I needed a new transmission. I had another transmission company say nothing was wrong with the transmission. The mechanic has been replacing different parts and nothing has fixed the problem. One mechanic said the wheels are getting hotter than normal. Please advise. Thanks