transmission fluid
 

I am having no transmission problems. About 135k miles on vehicle, is a transmission fluid change necessary?

If you do not intend upon keeping the car a long time, then no, a change is not necessary. If you want peak reliability and longevity, you are well overdue. It’s not your fault - manufacturer’s generally lie about this issue or mislead by omission. You are smart to ask.

You have things going on internally that are undesirable that you haven’t perceived or haven’t shown up yet. If you want to keep the car a long time, swap the transmission fluid completely (run about 10 to 12 quarts through it). Keep in mind a transmission pan is not exactly like an engine oil pan. An engine oil pan contains most all the fluid when sitting. A transmission pan contains 1/3 or less of the fluid when sitting - the rest of the fluid is elsewhere and needs to be cycled out.

Yes get the transmission fluid changed. It is not too late.
ideally you want to change it the first time at 60,000 miles. The goal is to stop wear and deterioration. Waiting until the transmission acts up and hoping that a fluid change will fix it is wishful thinking as that strategy frequently fails to provide the results that are expected.
So start changing it before there is much wear and before the fluid deteriorates too much. This will keep it working at its peak for several hundred thousand miles.
Call around to Lexus and Toyota dealers (Many members get work done at Toyota dealers) to find one that will do a fluid change. Some dealers refuse to do it and claim it is sealed for life. This is BS as they want you to buy a new car and car manufacturer life time is when the warranty and extended warranty expire.
Then you will find some dealers that are eager for your business and will change the transmission fluid. Or if you have a great local independent transmission shop or Toyota specialist shop they may do it.

I like doing incremental changes of 2-4 qts at a time via the transmission cooler lines using the tranny pump to pump out a gallon of old, and a transfer pump to pump in a gallon of new. This is prudent for a vehicle like yours with high miles. A total fluid change (some call a "flush") could result in issues.

My 2012 has 140k miles, transmission fluid was changed at 90k miles using total exchange (transmission cooler line).
it is in peak shape, and shifts line new, I plan to do another one at 150k.