Originally Posted by bearcav

This will be an unpopular opinion but I wouldn't bother with any of the temp checking, etc. This is how I do it on all my cars (Avalon, RX350, LS460 and my Cayenne which also has an Aisin trans. Also my VW's which use more complex DSG trans).

• Jack the car up the night before you're going to do the work. Remove all the panels and crack open the WS fill plug and drain plugs, leave both in place. Get a case of WS fluid and leave it in the garage.
• Next morning, remove the WS fill plug, remove the drain plug and remove the tube/inverse-dip-stick thing. Go make breakfast, let it all drain for like an hour.
• Reinstall the tube/dip-stick thing (finger tight, not gorilla fingers either, little girly hands tight). Reinstall the drain plug, torqued correctly.
• Measure how much oil you drained.
• Put the same amount back into your car via pump or gravity. Pump is easier, just add like an 1/8th of a quart for all the fluid in the lines you won't pump into the trans.
• Clear the WS plug, it has a rubber O-ring, lightly oil the O-ring and reinstall to correct torque. Its not a lot.
• Done.

With the above procedure you don't need to worry about temps, elevation, angle, pitch, etc etc. You're draining used room-temp fluid for new room-temp fluid.

For folks that think temperature matters, I live in Phoenix and in the summer the trans fluid temp doesn't get below 130*F even if you leave the car parked for an entire day (ambient temp is like 114*F in the summer). Do you think the Toyota/Lexus dealership is legitimately doing your trans service in the middle of summer in Phoenix in 2 hours and getting the right temp? They're not.

These things aren't bespoke race-car transmissions and you don't have to be that precise.

Edit: I've gotten more fluid out of the trans if I only lift the front of the car. Lifting all 4 corners resulted in less drained.

Originally Posted by lobuxracer

If you're replacing exactly what you took out, you're not accounting for clutch wear. If you're adding 1/5 of a quart, you might be making up for the loss. But if you do this 5 times, you'll be a quart over the original amount. The AA80E in the F cars doesn't mind 4 ounces over fill, but it sure hates 4 ounces under fill - flares when cold, whines like an old power steering pump at low speeds, and generally doesn't work the way it does when it is properly filled. TBH, I add 4 ounces after setting the level according to the factory procedure to stave off the onset of flare, because it's the first indication the gearbox fluid level is low.

I have no idea how the dealer does this and couldn't care less. I do all my car maintenance myself. Supra, IS F, and GS F.