If your car is having trouble starting, there’s a good chance that the transmission fluid is dirty. Transmission fluid is a slippery, viscous liquid that helps your car move from one gear to the next. To clean up transmission fluid:

  1. Park your car in a safe place and turn off the engine.
  2. Remove the cap on the transmission fluid reservoir. Use a funnel to fill a small container with transmission fluid and pour it into the reservoir. Be sure to replace the cap on the reservoir once you’ve filled it.
  3. Pour enough water into your car’s radiator to cover the transmission fluid and let it cool for about an hour before pouring it out. Be sure to rinse off all of the dirt and debris that was in the transmission fluid before you pour it out! ..