The gearbox oil on your Ford Mondeo is also known as the transmission fluid. This fluid lubricates the transmission gears, so that they do not overheat during normal operation. Transmission gears are very sensitive, and if they are not properly lubricated, they will grind against each other, causing your Mondeo's transmission will fail. Most transmission problems can be prevented by making sure that the lubricating oil is at the proper level. The first step in this maintenance procedure is to check the gearbox oil.
Start your Mondeo's engine and allow it to run for one minute.
Open the bonnet and pull the looped handle located in the back of the engine, near the firewall. This is the transmission dipstick. Pull the dipstick all the way out of the filler neck.
Wipe the end of the dipstick off and reinsert it into the filler neck until it bottoms out, then pull the dipstick back out of the filler neck.
Check the oil level on the end of the dipstick. The dipstick has a "Max" and "Min" line on its end. The fluid level should be between the "Min" and "Max" marks. If it is below the "Min" level, your car needs more gearbox oil.