Also posted this on ToyotaNation.
2018 Camry XSE 4-cyl, non-hybrid. 61,800 miles.
After the car had been sitting for over 20 hours, I drained the ATF and was able to collect exactly 3 quarts after removing both the drain plug and the threaded stand pipe. The drain plug is a 10mm hex and the threaded stand pipe is a 6mm hex.
Next, I reinstalled the drain plug and pumped in 3 quarts of Idemitsu Type TLS-LV ATF using my AST fluid filler (you can also use a funnel and the appropriate-sized hose). Note: the fill plug is a 24mm and is accessed thru the driver-front fender well.
After temporarily reinstalling the fill plug, I started the engine and shifted thru each gear selector position (P-R-N-D) while keeping the gear selector in each position for 3 seconds. I performed this procedure twice. Then, I allowed the engine to idle for an additional 2 min in Park to allow for the fluid to circulate.
After the previous step was complete, I repeated the drain and refill process two additional times - for a total of 3 times.
After the 3rd drain, I replaced the drain plug gasket and refilled with 3.2qts to allow for extra fluid to drain out during the fluid level adjustment process.
I used an Autel MD808 Pro scan tool, but you can use other methods as well (e.g. IR temp gun, built-in A/T temp light, etc.). The key is to get the fluid temp between 95-113 with 104F being the ideal temperature. After the 3rd drain, you may need to allow the engine to cool for 1-1.5 hr in order for the fluid temperature to drop; the transmission heats up very quickly and the few minutes of idling between each drain and refill may put the fluid temperature outside of the allowable range.
Note: It is very important to start the fluid level adjustment process with the fluid temperature in the mid 90F range in order to allow for enough time to go thru each gear selector position and for the engine idle speed to drop.
In total, I drained about 9.3 quarts (over 3 drain and refills) and refilled with about 9.3-9.4 qt. The old fluid was dark but not burnt. After the transmission service, shifts are noticeably smoother when the transmission is cold.
Hope this helps!