2008 Corolla Matrix Transmission Fluid Exchange - Toyota Corolla, Chevy Prizm (1998-2008)

Hello all,

So I'm a college student with a 2008 Toyota Matrix with 64,500 miles clocked on the odometer. Recently, I realized that the 4 speed automatic transmission shifted a bit roughly at colder temps. I live in Ohio and the vehicle is parked outside so it routinely stays in below freezing temps for extended periods of time.

After some research, it seemed as though changing the auto trans oil would be a relatively simple solution to provide smoother shifts. After all, I've changed the motor oil on the vehicle numerous times. So I purchased 4 quarts of Toyota T-IV Trans fluid from the local dealer and proceeded with the drain and fill. Altogether, I probably drained between 3.7 to 3.8 quarts from the auto transmission. However, once I added the fluid, the dipstick reads full after adding 3.4 quarts. Is the vehicle good to go? Or should I add 0.3-0.4 more quarts of trans fluid to exactly replace the fluid that I drained?

The dipstick always reads the same level regardless of whether or not the fluid is warm or cold. Therefore, I'm not relatively confident in the accuracy of the dipstick oil reading (which stays at the 'full level' whether or not the vehicle is warm or cold).

I drove the vehicle briefly afterward and it shifts smoothly and adequately. I'm not sure how to proceed at this point.

Thanks.

Auto tranny ATF level needs to be checked while the engine is idling.

Drive the vehicle so that the engine and transaxle are at normal operating temperature.

Fluid temperature: 70 – 80 °C (158 – 176 °F)

Park the vehicle on a level surface and set the parking brake. With the engine idling and the brake pedal depressed, shift the shift lever into all ranges from P to L position and return to P position. With the engine still idling, pull out the dipstick and wipe it clean. Push it back fully into the pipe. Pull it out and check that the fluid level is in the HOT position.

Also, look at both sides of the dipstick to verify the same indication.

If it shows full still, it may have been previously slightly overfilled...Total capacity is 8 quarts, by the way.

Thanks for the advice Dom. I wasn't previously aware that I needed to keep the engine running while checking ATF fluid levels. The fluid level looks adequate currently. It is a possibility that the transmission was previously overfilled, but I wasn't sure if that was possible from the factory (as I know this was the vehicle's first ATF change).

Would a slight overfilling or underfilling of the transmission pose any reliability risks for the transmission?

Thank you.

Overfilling the transmission may cause the fluid to foam, and that can lead to erratic gear shifting. Overfilling or underfilling can cause transmission damage from oil starvation and overheating... It could possibly have been overfilled by previous owner.

How much was it per quart for Toyota T-IV ATF?

See this is why I was confused, there was no previous owner so it would have to have been overfilled from the factory. My dealer charged $6.30/quart, seemed a little high but still reasonable. How much is it in your area?

It's not impossible that it could have been originally slightly overfilled, by whoever performed the pre-delivery inspection, possibly at the Toyota dealership.... 3.4~3.6 quarts to refill is normal for just a drain without removing pan and strainer.

I don't know how much the T-IV is up here. I was just curious because I recently learned that Toyota's synthetic 0W-20 engine oil is only $5.70 per liter in Canada... Mine has a manual transaxle, by the way.