P5mmx10g

When and How?

midcow3

60,000 miles or 72 months is Lexus recommendation.

YMMV,
MidCow3

Droid13

Well, it really depends on your GPS, as not even Lexus is sure when to change the transmission fluid. Yep, midcow3 is right that in the US on the severe service schedule that is what they say, but Lexus has a different story pretty much in each jurisdiction. In Canada, they still say its lifetime (even in severe service). Most people change their transmission fluid anywhere from every 30,000 miles to never. The 60,000 mile 72 mth thing is probably pretty decent interval, although a suspicious person would note this is when the powertrain warranty runs out, LOL (don't touch it until its your problem, not ours).

You didn't mention whether you were referring to the 8 spd auto or the hybrid, but in either case they both use WS type fluid.

I believe with the hybrid you just drain from the drain bolt and fill from the fill bolt until it overflows. With the 8spd its a little more involved as the drain also has an overflow tube that must be removed as well to drain the fluid. Then the overflow valve is reinstalled, fluid filled from the fill "WS" bolt until overflow, then engine is started, transmission is placed in D and R (among possible other actions) to circulate the fluid, top up the fluid to overflow, then using a scan tool monitor the fluid temp until a specific value is reached, then close off the drain valve. This ensures the correct fluid level at precisely a specific operating temperature. Sounds like fun to do.

ATLs460

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StefanoS

I change the A/T fluid in my Toyota/Lexus vehicles every 30,000 miles, doing a simple drain and fill and never a flush of the system. I only use genuine Toyota WS fluid and never remove the pan. You need not be concerned with the A/T filter, as Toyota uses only a screen and not a true filter. A good place to find a video walk-thru on this procedure is the Car Care Nut on You Tube. He (AMD or Ahmed) owns his own shop in suburban Chicago and is a former Toyota master technician. His YT clips are helpful for any car owner and DIY'er. IMO, there is no such thing as lifetime fluids for any vehicle. All of these fluids lose their lubrication properties over time and should be replaced and/or refreshed.

LeX2K

This is not correct, depending on the engine/transmission combo there may be a filter element. Example, turbo model

StefanoS

It appears that LeX2K is correct. Some models now do use an actual filter in the pan, as opposed to a screen. None of the vehicles that I have had or currently have are of this variety. In any event, check your vehicle before you start your fluid drain and fill. While there may be some small bits of metal in transmission fluid, there is normally a magnet which will capture these, rather than the filter itself. Also, the transmission does not have any contaminants from byproducts of combustion, as does an engine.