Learn me: transmission flushes, fills, and filters, noob edition

Car in question is a 2004 Sequoia with 178k miles. The service history is largely unknown because the car was bought from a dealer (there are virtually no private party Sequoia sales for some reason).

I do know that it is a one-owner car, and that the last major service, 150k, was done at a dealer. I take this as a good sign, as a guy who is still doing his maintenance at the dealer 10 years/150k miles into owning a car is probably taking good care of it. In addition, the car is generally in good shape ad seems to have been well cared for.

The transmission fluid is red—not brown—and as far as I can tell smells normal. I think the transmission shifts well too, though I get an occasional harsher shift and I feel like it doesn’t shift very crisply. There’s definitely room for improvement. ATF operating temps go between 140 cruising flat ground on a cool morning and 180 on a hot day with fairly heavy acceleration. Note that I haven’t towed with it yet, and I live in the gently rolling hills of central Ohio. Now, take that all with a grain of salt, this is only my third automatic out of 15-20 vehicles and I’m no expert on the slushbox ways.

Now, I want to change the ATF this weekend, but I’m not sure if I should do a complete “flush” (non-power) of the system, or just a drain and refill, and then keep doing drain and refills at oil changes until the fluid coming out looks identical to the fluid going in. I’m also not sure if I should do the filter. And if I should do the filter, should I do it now at the first fluid change, or wait and see if new fluid loosens any sludge?

Finally, some of the Toyota forum guys seem to like these magnefine in-line transmission fluid filters. I had never heard of them before, thoughts?

Well, a flush is easy to do on that vehicle. Disconnect both lines from the radiator and drop them into a bucket. Start vehicle. Add fluid once it quits squirting out of the hose. Stop when all the fluid looks spiffy new. Crude but perfectly effective flush technique.

But, as yours sounds like it's reasonably well maintained, I might just drain and change, especially if there is a plug on the transmission pan.

I would not bother with a filter change myself.

I'd just drain the pan. Looks like it is one of those "no dipstick" deals with specific temps for checking the level but it looks like the Toyota forum folks have it figured out.

You can register at Toyota's Owner's website and it will give a breakdown of all dealer-based service. That will give you a complete history of what work was done at the dealer, although you'd be missing any non-dealer service.

In our '06 RAV4, I used the 3X drain and fill method, and the last time I dropped the pan and replaced the filter.

A pan drop never hurt anything, full exchange isn't worth the effort of screwing with the lines and buckets and all that unless the fluid looks nasty IMO, especially if you live in a rusty area. Also a good idea to drop it to change the filter (if fiber, screens are pretty much forever) and wipe out the layer of wear crap that settles in the bottom. Valvoline maxlife (I put that E36 M3 in everything) would probably be a good choice for fluid, I'm pretty sure they spec that for Toyota, but you should probably check first.

Thanks guys.
To answer some questions: it does have a dipstick, and as foxtrapper alluded, an external transmission fluid cooler. The filter is a screen type, and I've heard it doesn't tend to pick-up much. (Those is part of the reasoning for the external ATF filter.). There pan has a drain plug. Since this is an Ohio car it's worth trying to avoid dropping the pan because the bolts are probably pretty rusty.

Sorry to butt in, I assume that this advice is sound for most automatic transmissions? I too am acquiring an automatic transmission next week with plans to keep it for a while. Mine is a 1990 Cherokee with a 4.0 and 200,226 miles.

I pretty much always flush a new too me vehicle, but i have access too a machine so its alot less mess.

In reply to pilotbraden:

Changing the fluid (full exchange or just a pan drop) has never killed a transmission that wasn't already on death's doorstep, if that's your concern.

Changing the filter is as important as the fluid change.

Sea foam teams tune or whatever it is called. Is magic. Use it.

In reply to iceracer:

Not really a filter, it's a screen in this transmission.

Update:
I drained what was in the pan and replaced it, plus added a can of lubegard red. Unfortunately, upon close inspection the drained fluid was in pretty bad shape. Not black, but a darker reddish brown than I thought from what came off the dipstick. Also, in a large quantity sitting in a drain pan it smelled worse than I thought from the dipstick.

So, I think I'm going to do a complete DIY flush.

Please let me know if I've got this procedure right:
1. Pull off the trans cooler lines and run them to a pan.
2. Start the car and leave it in park.
3. Wait until fluid has stopped flowing out of the trans cooler line, then turn the car off.
5. Hook the trans cooler lines back up.
6. Measure how much trans fluid came out.
7. Put that much new fluid back in through the dipstick.
8. Check the cool ATF level normally.

As I recall you want to be dumping fresh fluid through the dipstick tube while the engine is running and dumping ATF in the bucket, that way you flush out the converter (where most of the fluid is hiding). I think just running it dry like that would be the same as draining the pan. EDIT: Though I suppose you would use a quart or two less fluid for the job if you waited for it sputter before you started dumping more in. Also use a clear hose so you can better see when the color changes.

Alternatively you can just do pan drains every oil change until you're happy with it, that takes more fluid for the same result though.