Could be on, or in. Depends on the type of car. Please ask a new question with the make and model info. Domestically speaking, the only manufacturer that places the range sensor on the internals of...
Locate the dipstick in the rear of the engine. It won't be as obvious as the oil stick and it is usually shorter also. When you find it, simply remove the stick and clean it and then put it back in...
an automatic transmition is the one that does not need to be manualy shifted everytime a gear is needed when you drive. it shifts gears as the speed of the eninge increases.
ATF = Automatic Tranny Fluid MTF - Manual Tranny Fluid Many different brands so pick what you like just make sure its MTF Trust points are greatly appreciated M-Eight Auto Modifications
Yes. Will it be cheap? Probably not, unless your car is really old. Transmission and engine work are probably the most expensive modifications you can make to a car.