Transmission fluid is stored in the transmission's fluid reservoir and circulates throughout the transmission system to lubricate, cool, and provide hydraulic pressure for the transmission components. When you add or top off transmission fluid, you pour it into the transmission fluid dipstick tube, which leads to the transmission's fluid reservoir

. Here is what happens to the transmission fluid:

• The fluid is drawn from the reservoir and circulated through the transmission's internal components, such as clutches and gears, to lubricate and cool them

• It also acts as a hydraulic fluid to engage and disengage clutches and bands that control gear changes

• After circulating, the fluid returns to the reservoir to be recirculated continuously while the vehicle is running.

To add transmission fluid, you remove the transmission dipstick, insert a long, narrow funnel into the dipstick tube, and pour the fluid slowly to avoid overfilling

. The dipstick tube is the standard fill point for most transmissions, although some models may have a separate fill plug on the transmission case

. In summary, transmission fluid goes into the transmission fluid reservoir via the dipstick tube, circulates through the transmission to lubricate and operate the components, and then returns to the reservoir to continue the cycle