Looks like a 14mm
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DIY 2003-2008 Corolla, Matrix, Vibe Transmission Fluid...
I completed this procedure at 49,000 km on my 2008 Corolla 1.8L automatic (with the 1ZZ-FE engine). The transmission fluid was getting a bit dark looking on the dipstick. To the best of my knowledge, the transmission fluid was the original fluid that was supplied with the car. [EDIT June 1...