The Wrongman's Fix It Guide: Section 93, Chapter 122, Paragraph 17

Automatic transmission slipping out of gear? Start by locating the transmission fluid dipstick and check the level, color, smell and taste of the fluid. Follow the reminders: "up, red, cream soda, mouth full of pennies." If the fluid checks out, purchase a tube of Crest Pro-Health Tooth Paste WITHOUT WHITENING. Add the toothpaste to the transmission fluid and leave the cap off. If any white foam starts bubbling up from the opening, try to capture it in a bottle or a zip lock bag as you will need it later. If not, whatever, you can use the foam from a Wachusett Blueberry beer too. Anyway, replace the cap and start the car. Do not move the car. Hold down the brake, turn on the emergency brake too, put the car in LOW GEAR and fuckin' floor it. Now, relax and take it easy and I can guarantee that the engine will sound funny and it might heat up... if not overheat. But that's OK. As the pressure build up inside the transverse muffler overbearings it should be enough to fix the problem and reduce overall side fumbling. Remember the foam you saved earlier? Go get it and pour it in the windshield washer fluid reservoir. It'll be the best fucking cleaner you've ever seen, fuckpants.