WHAT DOES 4 MEAN ON THE GEAR SHIFT

probably 4th gear . you could start out in 1st and it wouldn't shift out of that gear till you put it in 2nd , if you put it in 3rd it would shift normally up until that gear , all this is not recommended However , lets say you have a car full of people and you're going up hills and what not you could put it in 3rd so that it wasn't hitting 4th and "bogging down " ie. My kid was driving and not going fast enough to climb winding hills , the trans kept going into 4th , then having no power ,and dropping down to 3rd to make the grade , I put it in 3rd and the rpms stayed high enough to climb . Some trannys will have problems in lower gears when you come to a stop so like I said this is not recommended but I hope you understand ..

My 2002 lexus is great but when i put ot in drive its stays or the light for the gearing stays in four. Yes the rpm stays high but the engine is ok. How to get it to go to drive actually?