I guess we'll just have to agree to disagree.
Why are there machines like these in almost every dealership shop, independent shop, and transmission shop?
Transmission Fluid Exchanger | Robinair
Power flushes that can dislodge build of sediment, etc. -- we can all agree that these are not recommended for higher-mileage vehicles. But low to no pressure exchange of the fluid is absolutely the recommended procedure.
The machines would exist regardless of their effectiveness, as long as the salesman can make it sound like the company saves 1 cent over what they do now; they have a possible sale. Having been at a dealership with went through 3~4 Chemical Suppliers and their machines specifically because of such cheapness, it's not about whether or not they work, it's about what the higher ups think is gonna save them money/make more money. If that means putting chemicals and additives in the fluid that aren't recommended by the manufacturer to make their service package's prices seem more valuable, then so be it.
As for the machines themselves, I suppose there isn't any harm in using them; the main issue I have is that too many people and techs fail to do the correct fluid check procedure afterwards. The erroneously assume that because 4qts got sucked up from the bottle, all 4qts went into the transmission and all 4qts of old fluid came out. When in reality it's more like 4.5qts of old/mixed fluid came out, 3qts went in, and the remaining .5 is in the lines you used for the flush. Bottom line, you still need to perform a fluid check afterwards (having used a similar machine at work with the giant piston for T-IV transmissions I can qualify how inaccurate that machine is relative to the dipstick)
Additionally, Toyota is a bit vague along the years; but they mostly show you draining and filling the transmission as the correct procedure for WS ATF. Then again as pointed out in another thread, they want you to use a "Brake Rotor Grinder" to resurface the rotors when doing brake services... never seen a grinder for rotors to be honest with you; but Toyota does requires us to use a On-Care Brake Lathe like ProCut for warranty brake concerns. So take that with a grain of salt I suppose?
But if you drain and fill the transmission a good amount until the fluid is fairly red you should be fine, its more about "refreshing" the fluid and the additive packages in it than it is about being OCD and getting it all out.
[MENTION=136099]Ratubbs[/MENTION]
Most Toyota Transmissions made in the last 10~15yrs or so do not have a paper or fabric filter like GM or other domestics. They use a brass or metal "pick-up screen" to filter the fluid, they are cleanable but require removal of the transmission oil pan to do so. From the few people who have actually bothered to do this on higher mileage transmissions, they seem not to get too clogged up (which I wouldn't expect them to unless the transmission was having serious issues). The majority of the particles are very fine and are either suspended in the fluid or caught by the magnets in the oil pan.
So you can clean them if you want, nothing wrong with that, but you'll have to use the correct FIPG and reseal the pan afterwards and make sure you install the screen correctly.