How to check the ATF fluid / Transmission oil level
Hans Angermeier is an ASE certified Maintenance and Light Repair Technician and has produced over 100,000 videos showing drivers how to fix things on their cars. He has broad expertise on basic repair procedures covering the majority of cars on the road. Over the past 10 years, Hans has been focused on building CarCareKiosk, which is visited by millions of drivers each month.
The engine in your 1999 Mercury Mountaineer should be running when you perform a transmission fluid level check, otherwise it will be inaccurate. The video above shows where the transmission fluid dipstick or the transmission fluid check plug is located in your Mountaineer and how to check the transmission fluid level. Your Mountaineer will have either a transmission dipstick or a check or fill plug to perform a transmission fluid check. The transmission dipstick will typically be in the engine bay or on top or even the side of your Mountaineer transmission. The transmission check plug will typically be on the bottom or the side of the transmission and may also be next to the axle. If the transmission fluid level in your Mountaineer is low, you need to add transmission fluid through the dipstick tube or the check plug hole. When adding transmission fluid to your Mountaineer, be sure to add it slowly as it will fill up quickly and is difficult to remove excess fluid if you overfill.
If you are having problems with the transmission in your Mountaineer, such as clunky shifting or hesitation, check the fluid level first - it is amazing how many drivers pay thousands of dollars for transmission work when a half quart of transmission fluid would have fixed the problem.