2000 grand marquis mercury

You want to run yourself over?

Can't be done from under the hood, you need to get under the car, you need to block the rear wheels on the front and rear side of the tires in order to keep the car from rolling then disconnect the trans linkeage from the trans then you can put it in whatever gear you want

Get it fixed properly is the best way to proceed. We do not want you to become your own casualty.