Its time for my DD to have the tranny fluid changed. I have heard the best way to go is by doing a 3x3 (three quarts drained out, three new quarts in, repeat for a total of three times I know that it may be more than 3 quarts that drain out) and then some swear by hooking the "machine" up on the tranny lines and exchanging old for new fluid.

The 3x3 does not remove all the old fluid, it just dilutes it out. The thought here is that you do not stir up all the gunk. The exchange may stir up the gunk leading to tranny failure.

Thoughts? My DD is a 2007 4Runner Limited.

Drain and fill is the safest way to do it. Unless your car is very new, a transmission flush can cause my more harm than good because the new fluid will break away junk in the transmission and force it through small passages and get's stuck.

quote:

Thoughts? My DD is a 2007 4Runner Limited.

I have a 2008 4Runner. I haven't done this yet, but after seeing the other transmission thread I did a little research.

This is a detailed write up. It's on a Tacoma but it was linked from a 4Runner forum. The Tacoma and the 4Runner (at least mine) both have the 4.0L V6
https://www.tacomaworld.com/th...-transmission.68462/

I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

quote:

Originally posted by Powers77:
I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

3x3 only on a Honda AT. Trans flush is a sure way to crash a trans on those.

My parents had 2 4Runners in the part & I seem to recall them doing a 3x3 or similar on those as well.

Just had the fluid and filter change on my 2003 Chevy Trailblazer with 130000 miles on the clock. This was the second time I had it done, first being with 65000 miles. He is a big fan of a flush after the first initial fluid and filter change so this should of been a flush job for me but I was adamant about filter change.

quote:

Originally posted by Powers77:
I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

2000 was a problem year for honda transmissions.

I R&R'd tranny fluid once (drain & fill) at around 60k miles. It failed almost immediately. Fortunately it was under warranty.

The problem here is that it means there was gunk or whatever that was in there and can cause issues at any time.

Does a 3x3 eliminate that possibility? Probably not completely. If the gunk is in there, the gunk can cause problems no matter what.

Good luck!

I just drain and refill my Honda CR-V. Easy access to drain plug and fill port. Takes 2.7 quarts. Do it ~ 20,000 miles.

I have always flushed the transmission in all my vehicles at 30,000 mile intervals, and never had a transmission problem. Recently traded my 2000 Merc. Marquis at 209K miles, and the only failure I ever experienced on that vehicle was a fuel pump. YMMV.

My understanding of a transmission flush is that they disconnect the trans fluid lines going to the trans fluid cooler, and run them into a machine that collects the old fluid going out the cooler input line, and injects new fluid going into the cooler output line. If this is the case, it isn't changing the fluid flow, it's just replacing the fluid in one segment of the flow.

How could this be any more damaging than the regular flow through the cooler? The only thing I can think of is that the fresh fluid is dissolving gunk in the transmission, causing gunk to break loose. This being the case, the flush isn't the problem, the new fluid is. But, of course, the fluid should be changed periodically.

Also, in an automatic transmission, most of the fluid is accumulates in the torque converter, not the pan, so you can never really get a full change by draining the pan.

There are people here who know a lot more about this than me. If anything I said here is wrong, please let me know why.

There are a lot of old wives tales and internet myth about automatic transmission flushes.
They are always the best way to go no matter how many miles are on the car. Anything that "breaks loose" will be caught in the hopefully new filter that should be installed as part of the service.
If flushes hurt old transmissions then starting and driving the car should cause more damage as it's still pumping the fluid at the same pressures but under load and hot.

since its an 2007 has it been changed before? is this the first change? check with Toyota or your owners manual and do what the manufacture suggest. foreign cars seem to do well with just a fluid drain and fill. Honda is big on this at every 30K, just drain and fill. and that's usually about 4qts.

my sisters 12yr old scion has about 60K and the atf fluid stick says "do not change fluid, lifetime fluid". the fluid looks and smells just like new. I change the oil for her and check fluids and the trans fluid has always been good. even the owners manual never says to change the tranny fluid and it goes all the way to 12yrs or 120000 miles.

if it has never ever been changed and is high mileage I would avoid flushing, just drain and fill. a flush on a high mileage never been changed tranny usually ends with trouble.

if its a low mileage then flushing shouldn't hurt anything but then again why would you need to flush a low mileage tranny?

there was another thread yesterday or day before asking this same thing on a Lexus suv. most of the answers where drain and fill.

I have been in the automotive service business and the norm is to drain and fill. usually if the shop insist on flushing its because they are selling the job for more profit, hours billed.

You can also use what is called the "Gibbons method", in the Volvo Groups, named after the guy who first described it.

Basically:
1: Drain the trans from the drain plug, if equipped, reinstall plug. If not, you pull the pan.
2: Refill through the dipstick approx. amount drained in 1.

3:Remove the return line from the trans cooler to trans, attach a discharge hose to the cooler outlet, so that the fluid being pumped by the trans goes to a waste bucket.

4: Run engine at idle until it just! begins to show a few bubbles, immediately shut engine down.
5: Dump in another quantity equal to drained volume.
6: Repeat until at least total fill volume of trans flushed through.

This method pumps the new fluid through the trans and exits as waste, until it runs clean.

We Volvo guys use 12 quarts to flush the trans. It holds about 8.

As a formulator of automotive lubricants, I prefer the drain and refill on my Toyota / Lexus vehicles. The Lexus RX330 is a four quart event. You would be surprised how the shift quality returns after even the first drain and refill.

quote:

Originally posted by Powers77:
I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

Acura/Honda had some serious problems some of their first 5 speed autos during those years. They even extended the warranty on some models to 100,000 miles.

Acura/Honda are a no go for flushes. Never do them. Standard practice is the 3x3 for these cars.

quote:

Originally posted by comet24:

quote:

Originally posted by Powers77:
I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

Acura/Honda had some serious problems some of their first 5 speed autos during those years. They even extended the warranty on some models to 100,000 miles.

Acura/Honda are a no go for flushes. Never do them. Standard practice is the 3x3 for these cars.

Yep, pretty much all V6 automatics from 98-04. It was a when, not if.
My '00 TL was on its 3rd trans when I got it. My sisters Accord was on its 2nd.
It affected the 4AT trans as well.
The more uncommon 6MT V6s weren't affected.

I have 15 quarts of MB tranny fluid in the garage. My plan is something equating to the dilution approach. I'll drop the plan and clean it, change the filter, and then do a fill and drain several times using this:

https://www.amazon.com/gp/prod...00_s00?ie=UTF8&psc=1

I've no intention to disconnect lines, or force flush. I'm not even willing to remove the plug in the torque converter for fear of a strip or cross thread. It's simply not worth it.

quote:

Originally posted by P250UA5:

quote:

Originally posted by comet24:

quote:

Originally posted by Powers77:
I ended up having to replace the transmission in our 2000 Acura circa 2006. Convinced it was directly due to being talked into a flush. Failed in about 1000 miles.
Drain and fill from now on.

Acura/Honda had some serious problems some of their first 5 speed autos during those years. They even extended the warranty on some models to 100,000 miles.

Acura/Honda are a no go for flushes. Never do them. Standard practice is the 3x3 for these cars.

Yep, pretty much all V6 automatics from 98-04. It was a when, not if.
My '00 TL was on its 3rd trans when I got it. My sisters Accord was on its 2nd.
It affected the 4AT trans as well.
The more uncommon 6MT V6s weren't affected.

I've always used the 30k flush schedule and I've never had a transmission issue on any Honda or Acura vehicle. Though I'm always up to date on any maintenance and service.

Honda did make some terrible transmissions during that period and instead of going through their inventory to remove the defective parts, they left them in the pipeline so they could identify them when they failed. Genius. Part of the reason I'll never buy another Honda vehicle. I can't imagine picking my new car up from having the transmission replaced and having it fail again, pulling out of the dealer lot.

quote:

Originally posted by Censored:
Its time for my DD to have the tranny fluid changed. I have heard the best way to go is by doing a 3x3 (three quarts drained out, three new quarts in, repeat for a total of three times I know that it may be more than 3 quarts that drain out) and then some swear by hooking the "machine" up on the tranny lines and exchanging old for new fluid.

Thoughts? My DD is a 2007 4Runner Limited.

I'm wondering if there's an update from the OP... what did you end up doing, Censored?

I just did the Drain and fill yesterday on a 2008 4Runner. I must say... it's a lot easier on the Acura. With the Acura, you can reach the fill plug from above with a long extension. You can then use a long funnel to fill from above and gravity works in your favor.

With the 4Runner.... the fill plug is hard to get to, from below, and you have to use a pump to replace the fluid. It's kind of a PITA.