need advice on what to do... the car when newly starts the engine is ok upon putting the transmission into D mode it wont move forward the engine just reeves though the speedometer reacts when accelerator is press. After a while, 10 to 20 seconds, it rolls forward ok only when in overdrive is off. but when overdrive is press it takes longer it has to be in D2 mode to run forward. putting it back to D mode the engine just reeves but the car wont go forward. only when it runs for a period of time (5 to 10 minutes) that smooth transmission is achieved when in D mode. please need expert advise, thanks in advance