Unfortunately, periodic 15K or even 30K drain/refills was overlooked/neglected and way past due and so doing the three-time-at-once or "flush" type fluid change-out as I've been discussing was decided upon.
So I'm still not really clear about your above response in regard to whether to drive around in order to circulate the fluid. Are you saying what's important is just to go through all the gears, but not necessarily by driving around ("not going anywhere")? And by all the gears I'm assuming that includes reverse, and the lower forward gears such as D3 and 2 and 1 also?

 

Yes, I would actually drive the car around, and not just sit stationary. I'm not saying to drive around, and go through all the gears (D1,2,3,4 and reverse) long enough to burn a 1/4 tank of gas, but the more you mix the old fluid with new the better IMO.

 

So if I just drive around a little bit today and try to make sure I go through all the gears maybe at least a couple of times while doing this driving around, that should mix the old fluid with the new just as good as driving around for a week? I would think so but wouldn't mind another comment. Then I'll stop beating my dead horse here about it.

 

Yes, go for a drive as you describe and you will be fine.

 

Driving around 15 or 20 minutes will mix up the fluid pretty good, especially if you make a point to use all the gears, including reverse. The only reason I would wait a week is if the day was getting long and I really didn't feel like doing it one more time...

The business about changing every 15k so you only have to do 1 drain/fill, that's a suggestion for going forward after you get it all cleaned out.

 

Okay, I did the driving around for 15-20 minutes and made a point to use all the gears. I did this before a first drain/refill of three quarts, then in between two more consecutive drain/refills of three quarts.

Got it. I'll start doing one drain/fill each and every 15k now.

And, I don't know if it's just my imagination but the car seems to shift more smoothly now since the change-out of all that old fluid.

 

Smoother & better after all the crud & gunk is removed? What a surprise!!
Just kidding...

After 15k when you drain it, use a real clean pan & look at the fluid that comes out. Use that to judge whether you want to keep 15k intervals or maybe 20k. Or even 10k.

 

k.