THE FUNCTION OF AUTOMATIC TRANSMISSION FLUID

There are several functions, besides just lubricating:

• It helps prevent some components from slipping, operating erratically, burning, and wearing too fast.
• It keeps the transmission within operating temperature, just like coolant does with your engine.
• Inside of and along with the torque converter—a doughnut-shaped component between the transmission and the engine–transmission fluid works like a clutch, transferring the engine’s rotating force to the transmission to move your car along the road.
• It acts as a cleaning agent. As the synchronizers, gears, bands and other components wear out, the fluid carries away shavings and other harmful particles into the filter to prevent abnormal component wear and breakdowns.
• And, in conjunction with the oil pump, it operates the transmission’s hydraulic system.

When you check the fluid’s level and condition—and take appropriate measures as necessary—you are giving your transmission fluid the best chance to do these jobs. And, it doesn’t take much effort.

HOW TO CHECK TRANSMISSION FLUID LEVEL?

The transmission fluid dipstick is similar to the oil dipstick, while the oil dipstick measures the level of the car’s engine oil, transmission dipsticks measure the level of transmission fluid in your vehicle. Keep in mind many transmission troubles are due to low fluid levels. If the fluid is low, it is likely there is a leak and it will need to be found and repaired by a professional right away. If you need to add additional fluid, be careful not to overfill the reservoir. Overfilling transmission fluid can cause the fluid to foam, putting excess pressure on the transmission, and forcing fluid out of the vent or a seal. This can result in slipping and instability.

1. Park your car on a level surface and lift the hood.
2. Turn on your car, leaving it in park, and let the engine run for a few minutes to warm up. Transmission fluid expands in heat and in order to receive accurate results, it must be under normal operating conditions. If the fluid is checked when the engine is cold, you may get false results indicating the fluid is low. Allow the engine to continue running while you check the level. Note: Honda is the only manufacturer that recommends you turn off the engine and then immediately check the level.
3. Locate your dipstick. Often found near the oil dipstick in front-wheel drive vehicles and near the rear of the engine for rear-wheel-drive engines, it is conveniently labelled for access and can have a red, pink, or yellow-coloured handle.
4. Pull out the dipstick and using a clean rag, wipe it clean, and place it back into the reservoir. Remove the dipstick again and locate the indicators on the stick to determine whether the fluid is “full” or “low.” If the fluid is full, replace the dipstick and close the hood. If the fluid is low, take your vehicle to an auto centre right away for a fill.

STEP-BY-STEP INSTRUCTIONS FOR CHECKING YOUR VEHICLE’S TRANSMISSION FLUID

1. Park vehicle on level surface, engage parking brake and start engine. Leave car in neutral or park. Let engine warm up and continue to run throughout operation unless vehicle’s owner’s manual says otherwise. (Be aware that some automatic transmission fluid levels are checked with the engine off. Check owner’s manual.)
2. Locate automatic transmission fluid dipstick, typically near where the transmission or transaxle meets rear of the engine. It looks similar to the oil dipstick.
3. Remove automatic transmission fluid dipstick. Wipe clean, reinsert fully and remove again. CAUTION: FLUID MAY BE HOT! 
4. Observe markings at end of dipstick. Your dipstick might have two markings for “full”—one warm, one cold. If the automatic transmission fluid level does not come up to the “warm” line, you’ll need to add automatic transmission fluid.
5. Insert long funnel into automatic transmission fluid dipstick hole. Carefully add automatic transmission fluid in small increments and recheck level each time until fluid level reaches “warm” line. CAUTION: DO NOT OVERFILL OR SPILL AUTOMATIC TRANSMISSION FLUID ON HOT ENGINE PARTS! 
6. Reinsert automatic transmission fluid dipstick fully. You’re done!