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I did a transmission drain from the pan drain plug. I measured 3.5 quarts came out so I put 3.5 quarts Toyota ATF WS in through the fill plug. Transmission, ATF, refill was all at about 60 degrees as the car had been sitting for hours before I did this.
Drove the car normally for days then did a 2nd drain and fill. This time the car had been sitting for an hour after being run. The transmission pan was slightly warm to the touch. I measured about 3.6 quarts drained this time. Added about 3.6 quarts. The new ATF was sitting in the garage, maybe 70 degrees F so slightly colder than the old fluid that came out.
I drove the car for 15 minutes, came back and put the front on ramps and the back on jack stands. It looked level. The trans pan was 110 degrees F according to my non-contact thermometer so I pulled the level plug. When it reduced to a trickle I put the plug back in. I measured the pan temperature again to make sure it hadn't cooled significantly and got readings of 107-108 degrees. Happily put the car back on the ground and put tools away and then I measured what came out and now I am afraid something is wrong. By my measurements I took out about 7.1 quarts in 2 drain cycles and added back about 7.1 quarts so I was expecting to get close to no fluid out when I set the level. Instead I got 1.25 quarts out!
Either I did something wrong or the car came to us with over a quart of trans fluid over filled. What happened??
I just watched someone do this on youtube and he left the engine running while draining from the ATF leveling plug. I did not have the engine running. Does it matter if the engine is running while doing this? The car is in Park, nothing in the trans is moving. I think.
Thanks! I did run it through all the gears twices before driving it at all, forgot to mention that. I'll give it another go with the engine running.
If you lift it level, start it and shift, then open the fill hole with it still running, you will then get the fill correct.
One thing I am confused about is that the awd models drain slightly under 2 quarts when the drain plug is pulled - they are less than most transmissions. This data from Amsoil for your car is consistent with what I’ve experienced, having done five or six drain/fills on this transmission.
The “initial fill” volume given here refers to the correct drain/fill volume:
...One thing I am confused about is that the awd models drain slightly under 2 quarts when the drain plug is pulled - they are less than most transmissions. This data from Amsoil for your car is consistent with what I’ve experienced, having done five or six drain/fills on this transmission.
The “initial fill” volume given here refers to the correct drain/fill volume:
Interesting. I definitely got around double that amount, 3.5 qts, with each of the 2 drains I did. I did not do any level adjustment after the first time draining, just put in exactly what I took out. That leads me to believe it was over filled by a lot before I got my hands on the car. I guess I'm in for one more drain and fill and see if I get something closer to the 1.7 qts you and Amsoil mention now that the level is possibly maybe set better.
Luckily I shopped around for the Toyota brand WS trans fluid. Lexus dealer near me quoted $30/qt. Nope. Toyota dealer (across the street from the Lexus dealer) was $18/qt. Went online and bought it for $13/qt at the Toyota dealer only 5 miles further away than the local one.
If you need more fluid for it, Valvoline MaxLife works excellent. It is more shear resistant (doesn’t break down as fast) as the Mobil fluid Toyota re-packages (Toyota WS is made/blended by Mobil, JWS3324). It’s widely available and priced well.
If you lift it level, start it and shift, then open the fill hole with it still running, you will then get the fill correct.
One thing I am confused about is that the awd models drain slightly under 2 quarts when the drain plug is pulled - they are less than most transmissions.
FYI, just did 2 drain & fills on a 2018 IS300 AWD, and both times I drained just a tick under 4 qts according to the graduated 1 gallon bucket used:
Drained it after driving it, so it was up to temp
Front wheel ramps were 7.5" tall and rear wheel ramps were 4.5" tall, so the rear was 3" lower
The one major part of your process that is incorrect is how you measured the temperature...measuring the temperature of the pan does not give you the temperature of the fluid itself, and that is the needed info when checking the fluid level and draining any excess fluid from the overflow port. You need a reader connected to the OBD-II port that measures the transmission fluid temperature in real time. When that fluid reaches a specific temperature range, then you remove the overflow port drain plug while the car is running, let the excess drain out, reinstall the plug, and you're done. Also, when refilling the fluid after initially draining the 3.5 quarts, put in a little more than that (say, 3.75 or even 4 quarts). You want to see fluid come out the overflow port to ensure you're at the proper level. But again, this won't work without the correct temperature reading of the transmission fluid itself.
If you lift it level, start it and shift, then open the fill hole with it still running, you will then get the fill correct.
Not exactly. See my attached screenshot.
Originally Posted by JCMikulak
The one major part of your process that is incorrect is how you measured the temperature...measuring the temperature of the pan does not give you the temperature of the fluid itself, and that is the needed info when checking the fluid level and draining any excess fluid from the overflow port. You need a reader connected to the OBD-II port that measures the transmission fluid temperature in real time. When that fluid reaches a specific temperature range, then you remove the overflow port drain plug while the car is running, let the excess drain out, reinstall the plug, and you're done.
These vehicles have an "automatic transaxle fluid temperature detection mode and engine idle speed control mode". Basically, with engine running, you move the gear from P to D, then back to P, then back and forth quickly between D and N, and "D" will illuminate on the dash when you're good to check the fluid level.
Again, see attached screenshot.
Last edited by nitroracer; May 20, 2026 at 11:25 AM.
If the fluid is purchased ahead of time, Toyota dealers have sales online around the holidays throughout the year ranging from 15% - 30% off with free shipping on $75 or more orders. The most recent sale was Memorial day at 15% off. Some online dealers do not charge state tax depending on their location.
Currently, World Toyota has WS fluid at $11.45 per quart per their normal pricing.
Transmission fluid level
