An automatic transmission depends on the transmission fluid for transferring engine power to the wheels, shifting gears, lubricating moving parts and cooling down the transmission. Check the transmission fluid when your car is serviced and change it as recommended. Different cars have different ways of checking the transmission fluid level; some require the engine to be shut off (e.g. Honda), some cars don’t have a transmission dipstick at all and the fluid can only be checked in a repair shop. Check your owner’s manual for proper procedure. This is how the transmission fluid checked on most cars:
After the vehicle was driven for a while to let the transmission fluid warm up, place your vehicle on a level ground. Set the parking brake. Make sure the transmission is in “P” (Park) position. Leave the engine running. Find the automatic transmission dipstick (your owner’s manual will tell you where it is located). Pull the dipstick out.
Wipe the dipstick off with a clean lint-free rag. Insert it back fully. Pull it out again and check the fluid level. A transmission fluid expands when warmed up, so if the car has been driven for a while (20-30 minutes), the transmission level should be between “HOT” marks. If the vehicle is cold, the level should be between “COOL” marks. Check the fluid condition: a very dirty fluid with strong burnt smell is a warning sign of transmission problems. Normally the automatic transmission fluid should be clean and transparent, On most cars the new transmission fluid comes red and over time it becomes brownish. If your fluid looks very dark or dirty, check your owner’s manual, maybe it’s time to change it. Some manufacturers require you to change the transmission fluid at 30,000 or 50,000 miles, check what your car owner’s manual says. If the transmission fluid level is low, you can top it up, but be careful not to overfill it. Overfilling the transmission can cause problems. It’s very important to use only specified transmission fluid type – check your owner’s manual or simply visit your local dealer, they always have proper transmission fluid in stock. Incorrect fluid type can damage your transmission. How to top up the transmission fluid: Using a thin funnel, add a small amount of the fluid through the dipstick pipe. Wait for a few minutes – let the fluid drain down. Recheck the level again, Don’t overfill!