How to change transmission fluid? Corolla, 1999 Auto

has several articles on basic car repair and maintenance, and has Toyota-specific information and news groups. But try to get a genuine Toyota factory manual for a

1998-2002 Corolla since nothing else is as easy to understand. The next best source would be a Chevy/Geo Prizm factory manual (same car), followed by a Mitchell manual. Other publications are markedly inferior and may provide incorrect or only generic information for certain procedures, but has some online for several models.

You'll need to know how to read the transmission fluid level correctly because it's essential to fill the transmission accurately to prevent damage. Be sure the car is parked on a completely horizontal surface. But unlike with an engine, you can't simply pull out the dip stick to check the fluid level but instead you have to run the engine and slowly shift through all the gears and end back in Park (all while the parking brake is firmly set and your foot is pressing on the brake pedal, of course). Then, while the engine is still running, read the dip stick. Wipe off and reinsert the stick as many times as needed to remove splashed fluid and get a good reading.

Toyotas transmissions I've seen had a drain plug, and if yours does, simply remove it and drain and refill the transmission. That may not be the most thorough way to change the fluid, but you're less likely to get in trouble this way. Be careful not to confuse this drain plug with the engine's. Some of these drain plugs require a hex or Torx wrench instead of the usual socket wrench.

You'll need a clean funnel that will fit into the transmission dip stick tube. A kitchen funnel may do, but auto parts stores sell long ones that can reach into tight spaces and may fit better (or not). Also you want a completely empty container in which to drain the old fluid so you'll know exactly how much fluid drained out because initially you'll want to put back the same amount of fluid that came out of the transmission. probably just 2-3 quarts. Verify the fluid level as described before, and add only a half pint at a time, shifting through all the gears each time, until the level is correct. If you overfill, even slightly, drain the excess and check the level again.

Buy the correct type of fluid. I don't know if you need Toyota type T or T-4 or can use Dexron III, but don't second guess on this, and don't take the advice of any clerk at a discount auto parts store. Transmissions are easy to wreck with the wrong fluid, and even the most expensive correct fluid is far cheaper than a new transmission. Don't buy synthetic fluid.

Count the number of shifts when you accelerate moderately from 0-60 MPH without letting up on the pedal. 3 shifts means a 4-speed. If you have an overdrive (OD) button on the shifter (button is probably lighted, do not confuse this with the shifter lock button on the side of the shifter knob), then you have a 4-speed. I believe Toyota still used the 3-speed A131L speed in 1999 and that its oil pan had 15 bolts, with a U- or blunted V-shaped indentation surrounding the drain plug. I would expect the pan of the 4-speed to have more bolts (the 4-speed A240L, which is probably not what Toyota used in the 1999 Corolla, had

17 or 18 bolts, and the indentation around its drain plug was a circle). Amazingly, Wikipedia had Toyota transmission information:

==================================== The engine oil I use has "ounce" markings on a translucent strip on the side, so I pour the drained transmission fluid into the empty oil bottles filling them to an even number of ounces, then use a measuring cup to add back the same amount when re filling the automatic transmission. When checking the final level, the fluid needs to be "hot." That is, normal operating temperature, typically driven at least ten miles before the final check, but not idled in city traffic on a hot day with the air conditioning on, or driven at continuous high speed, just fully warmed up to normal operating temperature. Because the fluid expands when heated, if you fill it when not fully heated, it will be over filled at operating temperatures. Sometimes, the drain plug is hot to remove by hand. If you get a small telescoping magnet, and let the fluid drain over night (more drains out that way) you can retrieve the drain plug with the magnet easily when the fluid has cooled. You'll most likely need a 10mm Allen head socket, and it's helpful to have a 3/8 to 1/2" converter bit so you can easily apply the extra torque with a larger wrench when removing the drain bolt. It is best to use a new aluminum gasket when reinstalling.