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Discussion Starter #1 (Edited)
While waiting for an oil change at the dealer, I quizzed the service adviser on what exactly they do for their $180 Complete ATF fluid service. I expressed my reservation that they will simply open the drain plug, dump the ATF not in the torque converter and refill - not a complete ATF replacement in my mind.

The adviser said they do not drop the tranny oil pan, change the filter, or even open the drain plug for the fluid renewal. I went 'WTF!' . . . . How exactly will the complete ATF renewal be done I asked?

He said they hook up an ATF extractor machine with two lines to the transmission for the job, the ATF inlet & return line from the ATF cooler on the rad. One line feeds in fresh ATF while the other line evacuates the old fluid. He said the Rav4 sits on the hoist with engine running so the torque converter will continue to push the old fluid out while the other line feeds in the fresh fluid. He mentioned something about adding a flush agent in the evacuating portion of the process. The whole ATF renewal process takes an hour.

This sounds like the DIY ATF renewal posts that involved dropping the transmission oil pan, replacing the filter, getting rid of metal filing/sludge around the drain plug, and replacing the ATF in the torque converter via the inlet/return lines.

The dealer's method sounds plausible ATF will be completely renew albeit with caveat that the filter change and sludge cleaning weren't done. Do you see any shortcoming of using a flushing agent to help remove soluble contaminants such as the sludge at the bottom of the oil pan? I still don't like the fact the filter will not be replaced but why cracks a perfectly sealed tranny case to introduce the possibility for future leak?

The adviser also said he has never had any problem with customer coming back complaining of tranny issues after the flush. I'll take that statement with some salt . . . .

Your opinions on letting the dealer do the complete ATF renewal?
 

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IMO that is THE best way to do it. Essentially the same as the DIY method using the cooler lines.
The multiple drain&refill method really only dilutes the old fluid never really replacing 100% of it.
 

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It is a return line flush. That dealer is using the machine to feed the transmission fluid and letting the engine circulate it. The return line oil flows to a waste container instead of back into the transmission. You can do this at home. Much better than just a simple drain and fill.
 

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Changing the fluid this way,do you ever need to replace the filter?
You should change the filter depending on the circumstance. If you have high mileage then it would benefit. Your transmission last longest if you flush all the fluid (return line method preferred). This is more important than replacing the filter. The factory filter can last a long time.
 

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I ***think*** I remember reading from others here that they advised AGAINST doing a power flush of the transmission and instead dropping the pan, replacing the filter and cleaning out the sludge, and doing a drain and refill.

Then 1 week later do another drain and refill (NOT dropping the pan and replacing the filter).

Then 1 week later do a final drain and refill (NOT dropping the pan and replacing the filter).

For some reason I'm thinking others have had issues with the power flush method, like the transmission starting to make noise or having some performance-related issues, not sure.

The theory was that triple-drain-and-refill approach was the safest when it comes to maintaining perfect transmission performance.

Does anyone else remember posts along these lines?

Thanks much.

.
 

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I ***think*** I remember reading from others here that they advised AGAINST doing a power flush of the transmission and instead dropping the pan, replacing the filter and cleaning out the sludge, and doing a drain and refill.

Then 1 week later do another drain and refill (NOT dropping the pan and replacing the filter).

Then 1 week later do a final drain and refill (NOT dropping the pan and replacing the filter).

For some reason I'm thinking others have had issues with the power flush method, like the transmission starting to make noise or having some performance-related issues, not sure.

The theory was that triple-drain-and-refill approach was the safest when it comes to maintaining perfect transmission performance.

Does anyone else remember posts along these lines?

Thanks much.

.
Yup, this has certainly been hashed over and over, not only here but on many other forums as well. My long-time mechanic has always recommended regular drain-and-refills, no flushes. I've put many 100s of Ks on several vehicles doing that with nary a trans problem. Only exception was a Subaru who's trans died because the idiot Chrysler dealer(who bought the Subaru franchise)put gear oil in it. It did last almost a year though, before its death!:frown
 

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I ***think*** I remember reading from others here that they advised AGAINST doing a power flush of the transmission and instead dropping the pan, replacing the filter and cleaning out the sludge, and doing a drain and refill.


Thanks much.

.

There are different methods of flushing. Flushing machines that connects thru the cooler lines and uses a machine to provide pressure does do harm. Then there are ones that uses the transmission pump to flush fluid out. This is safer since it does not add additional pressure.

So not all flushing methods are the same but many people don't know the difference or which is harmful.
 

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Discussion Starter #10
There are different methods of flushing. Flushing machines that connects thru the cooler lines and uses a machine to provide pressure does do harm. Then there are ones that uses the transmission pump to flush fluid out. This is safer since it does not add additional pressure.

So not all flushing methods are the same but many people don't know the difference or which is harmful.
Using the return line method with a flushing agent maybe of suspect, with or without pressurization. It essentially circulates dissolved gunk throughout the valve body when the sludge was originally just sitting at bottom of oil pan undisturbed. No flushing agent means the worn ATF is circulated through the torque converter without suspended and dissolved gunk.
 

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Using the return line method with a flushing agent maybe of suspect, with or without pressurization. It essentially circulates dissolved gunk throughout the valve body when the sludge was originally just sitting at bottom of oil pan undisturbed. No flushing agent means the worn ATF is circulated through the torque converter without suspended and dissolved gunk.
With that and other reason I prefer not to use the flushing machines.
 

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I've gone the drain and refill route, roughly every 35k miles. I feel this is ahead of the maintenance schedule for USA RAVs, which is basically NEVER unless you tow. LOL on that. With good functioning tranny, I go with the most benign approach.

The drain is at the bottom and I feel if you do it early and regularly like this you get some or most of the gunk that settles at the bottom. Obviously dropping the pan, removing the gunk, and then carefully flushing would be better. But I've had a few mechanics tell me better not to disturb the crud in there with a flush. And not to use the auto flushes without removing the pan and filter which picks up the crud and circulates it--especially on an older vehicle.

On the other hand, if your RAV is having hard shifts or whatever, maybe a flush would be better. One forum member thought the friction plates in his tranny were contaminated and the flush method is what cleaned them and had good results. So...pick your poison. For me, I'm happy since the tranny shifts like butter. The fluid is still pink and smells like chestnuts. I know it's not 100% clean at any time, but better than NEVER changing. The vast majority of owners probably never change the fluids and happy for 10 years or so when they get a new one.
 

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Pulling the pan is the best way. But getting rid of bad WS is far far more important. The factory filter is a chain link fence at 100 micron+ if your under 60,000 I would let them just flush it. You can also tell them you want them to pull the pan and do the filter and they can add the 3 qts to the pan before they start and then they can hook up the machine. It may be an extra $125 though. Just getting ALL he WS out is your biggest savoir here. Best thing is do it yourself. Then you know it is done the way you want. It is not that hard. Especially if you guys in this subforum have dipsticks in your years car.

Here is a thread that will explain how to do it in a 4.4 > 2013 to 2017.


http://www.rav4world.com/forums/123...smission-temps-towing-1-400-miles-summer.html



As far as the machine goes, most of the old style machine did back flushing and the ones used now let the car pump pump in the same direction as it normally goes so no damage is done. Tell the dealer that if you have a choice you don't want a power flush, See if they can just use the machine for an old oil dump tank and a new oil holding tank with only using the cars pump to do the pumping. Most are this way now. But it doesn't hurt to ask.

.
 

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Any transaxle with an internal differential that shares a sump with the rest of the unit throws off considerable amounts of debris that needs to be trapped by magnets or the filter.

Not removing this debris is a mistake that will shorten the life of your transaxle.

If the filter plugs up it means certain death regardless of the fluid type or condition so in my professional opinion as a 25 year independent transmission rebuilder...FLUSHING WITHOUT CLEANING THE PAN AND REPLACING THE FILTER IS A HUGE MISTAKE.

My own vehicles get partial fluid and filter change every 30K and I always use Lubegard Platinum and full synthetic fluid.

But, hey...my shop is always in need of more work :)
 
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