The owners manual or a repair manual for your vehicle will have a maintenance schedule set up by the engineers who designed it. It will also list the recommended fluid specifications.
You cannot change transmission fluid on an engine. Please be more specific. I must know the make,model, and year of the car to help you.
It would be from a seal.
Five quarts of oil with filter change (don't know radiator and other fluids capacities)
If you don't know when it was changed last, Then I would change the fluid and filter and then you know what you have got. Then it will be good as long as you can see through the fluid on the dip stick.
disconnect the first coil lead and start the engine, if it makes a difference with the running of the engine then stop engine and replace the lead, do this with the other three, stopping the engine each time, eventually you will find the one that makes NO difference to the running of the engine, that is the one you must change but please remember to stop the engine each time, there is a lot of voltage there.
I am curious to know which oil you changed. Usually when one says oil change, they are referring to the engine oil. When referring to a transmission, one usually says they are doing a transmission fluid change. You mention the oil came out red. Red is the color of transmission fluid. I'm wondering if you drained the transmission fluid thinking you were draining the engine oil. If so, the transmission is empty and that would be the reason for no reverse or drive gears.
When you pull the dip stick out to check the transmission fluid, If you can't see through the fluid on the stick then change it. If it smells burnt change it. If it is clear and pretty red then it is okay.
National Tire & Battery is a reliable place that will change your transmission fluid for you. They can also test your transmission fluid to let you know if it needs changing.
I don't know what your definition of a small amount is but, I wouldn't leave it in there for long. Change the engine oil and filter as soon as possible with the correct oil for your car. I have known some old timer mechanics who used to do that to help clear sludge from inside an engine.
i dont no
Hard to say, since we don't know what fluid you are talking about.
Usually about 9 litres, depending on the engine. (3L dodge engine is 9)