Auto trannies: flushing vs draining
- Thread starter grampi
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My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Always drain and fill.
The word flush should be referring to toilets only.
The word flush should be referring to toilets only.
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
Originally Posted By: SLCraig
Always drain and fill.
The word flush should be referring to toilets only.
I agree that a power flush can dislodge things and cause damage.
But naming the cooler line method (in which the fluid is pumped out by the trans itself) a "flush" is a poor semantic habit of which we're all partly guilty...
In reality, this is a simple fluid exchange. Since you're using the transmission's own pump, and the normal pick-up in the pan, you are doing NOTHING different than simply idling the engine...the trans moves fluid at the same rate, through the same circuits, whether the fluid goes into a waste pan or into the oil cooler.
So, the cooler line method is not a flush, and won't hurt the trans any more than a drain and fill, but it does have the advantage of exchanging all the fluid at once, so it is more effective and complete. Works better, no risk...that's why I would do it that way...
Always drain and fill.
The word flush should be referring to toilets only.
I agree that a power flush can dislodge things and cause damage.
But naming the cooler line method (in which the fluid is pumped out by the trans itself) a "flush" is a poor semantic habit of which we're all partly guilty...
In reality, this is a simple fluid exchange. Since you're using the transmission's own pump, and the normal pick-up in the pan, you are doing NOTHING different than simply idling the engine...the trans moves fluid at the same rate, through the same circuits, whether the fluid goes into a waste pan or into the oil cooler.
So, the cooler line method is not a flush, and won't hurt the trans any more than a drain and fill, but it does have the advantage of exchanging all the fluid at once, so it is more effective and complete. Works better, no risk...that's why I would do it that way...
I searched high and low across 3 counties for any trans machine that "flushed". I never found one.
All of them including the B&G we owned here are simply passive containers with a sight glass and a huge rack of adapters to fit almost any car.
They cannot hurt anything if used carefully. But they are no substitute for changing the filter and cleaning out the crud in the pan.
All of them including the B&G we owned here are simply passive containers with a sight glass and a huge rack of adapters to fit almost any car.
They cannot hurt anything if used carefully. But they are no substitute for changing the filter and cleaning out the crud in the pan.
Originally Posted By: RamFan
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
I agree, and doing this would be very expensive...
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
I agree, and doing this would be very expensive...
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Insane!!
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Insane!!
JHZR2
Staff member
Do you have a fluid evacuator (vacuum) unit? If so, do a few pulls from the dipstick, maybe 500 miles apart to start getting new fluid in, then eventually do the pan drop thing.
I did only the flush in the same tranny with similar miles recently.
Here are some helpful threads
DIY: Gen 9 Corolla Trans fluid exchange & strainer replacement
My 05 Corolla CE Auto Transmission Flush Experience
Here are some helpful threads
DIY: Gen 9 Corolla Trans fluid exchange & strainer replacement
My 05 Corolla CE Auto Transmission Flush Experience
Originally Posted By: grampi
Correct me if I'm wrong, but doesn't a flush force fluid to flow backwards through the tranny, hence the risk of dislodging particals and clogging passageways?
Nope. All are passive, no pumps or even electrical parts, just two containers. One for clean and one for dirty.
Your trans pump does all the work. Fluid follows all original pathways...
Correct me if I'm wrong, but doesn't a flush force fluid to flow backwards through the tranny, hence the risk of dislodging particals and clogging passageways?
Nope. All are passive, no pumps or even electrical parts, just two containers. One for clean and one for dirty.
Your trans pump does all the work. Fluid follows all original pathways...
Originally Posted By: SteveSRT8
Originally Posted By: grampi
Correct me if I'm wrong, but doesn't a flush force fluid to flow backwards through the tranny, hence the risk of dislodging particals and clogging passageways?
Nope. All are passive, no pumps or even electrical parts, just two containers. One for clean and one for dirty.
Your trans pump does all the work. Fluid follows all original pathways...
Then why do so many people say not to have flushes done as they may dislodge particals that would then move around and clog passagaes? Is this notion just a myth? I remember taking my wife's minivan to an Aanco several years back to have a tranny flush done. The tech said the tranny filter didn't need to be replaced because the flush pushed the fluid backwards through the tranny, therefore cleaning the filter as well as the tranny. Is this not correct?
Originally Posted By: grampi
Correct me if I'm wrong, but doesn't a flush force fluid to flow backwards through the tranny, hence the risk of dislodging particals and clogging passageways?
Nope. All are passive, no pumps or even electrical parts, just two containers. One for clean and one for dirty.
Your trans pump does all the work. Fluid follows all original pathways...
Then why do so many people say not to have flushes done as they may dislodge particals that would then move around and clog passagaes? Is this notion just a myth? I remember taking my wife's minivan to an Aanco several years back to have a tranny flush done. The tech said the tranny filter didn't need to be replaced because the flush pushed the fluid backwards through the tranny, therefore cleaning the filter as well as the tranny. Is this not correct?
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I have heard this before here. I now consider it a myth. For nearly a year across multiple counties I work in I stopped EVERY DAY at almost every service facility I found.
I NEVER saw anything but 'passive' machines. No power of any kind, just bladders and containers.
Since your own trans does the 'work' I have a hard time believing the tales of damages. We do our own "flushes" in the driveway with a bucket and a piece of hose!
I NEVER saw anything but 'passive' machines. No power of any kind, just bladders and containers.
Since your own trans does the 'work' I have a hard time believing the tales of damages. We do our own "flushes" in the driveway with a bucket and a piece of hose!
Quote:
The tech said the tranny filter didn't need to be replaced because the flush pushed the fluid backwards through the tranny
That's false. There are check balls in passages and seals that would prevent this from happening for the most part.
I have never seen a machine that works this way although i have heard this also.
Its possible i suppose that some early machines my have had some pressure on the in out circuit that caused issues but i don't know.
The only possible issue with a line off exchange i can think of would be if the filter were not changed and the pan not cleaned.
Its remotely possible the new fluid being poured in could dislodge junk on the bottom of the pan and get drawn into the existing filter.
With a clean pan and new filter the new fluid goes up through the new filter pushing the old dirty fluid ahead of it.
With the line off this old fluid goes into a container not back into the unit.
With drain and fill you always have contaminated fluid, it may take more than 30 qts even on a small unit to bring the level of contamination down to almost new fluid levels.
A line off can get it as close as you can get without dismantling the unit.
Drain and fill is one of the biggest waste of money i can think of. Pay all that money and end up with only contaminated fluid.
On a large unit like the 4R100 the pan hold 6 qts but the total in the unit is almost 20 qts so a drain and fill nets you 30% new fluid and when mixed with 14 qts of old fluid the job just made bad fluid a little less bad.
Pointless IMHO.
The tech said the tranny filter didn't need to be replaced because the flush pushed the fluid backwards through the tranny
That's false. There are check balls in passages and seals that would prevent this from happening for the most part.
I have never seen a machine that works this way although i have heard this also.
Its possible i suppose that some early machines my have had some pressure on the in out circuit that caused issues but i don't know.
The only possible issue with a line off exchange i can think of would be if the filter were not changed and the pan not cleaned.
Its remotely possible the new fluid being poured in could dislodge junk on the bottom of the pan and get drawn into the existing filter.
With a clean pan and new filter the new fluid goes up through the new filter pushing the old dirty fluid ahead of it.
With the line off this old fluid goes into a container not back into the unit.
With drain and fill you always have contaminated fluid, it may take more than 30 qts even on a small unit to bring the level of contamination down to almost new fluid levels.
A line off can get it as close as you can get without dismantling the unit.
Drain and fill is one of the biggest waste of money i can think of. Pay all that money and end up with only contaminated fluid.
On a large unit like the 4R100 the pan hold 6 qts but the total in the unit is almost 20 qts so a drain and fill nets you 30% new fluid and when mixed with 14 qts of old fluid the job just made bad fluid a little less bad.
Pointless IMHO.
Originally Posted By: RamFan
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
It's funny how people always load their pants when someone doesn't do 100K on ~$30 of syn fluid, when this guy clearly said he has had "years of transmission failures" How may thousands of dollars did those failures cost? Probably enough to make a short OCI thrifty by comparison.
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
It's funny how people always load their pants when someone doesn't do 100K on ~$30 of syn fluid, when this guy clearly said he has had "years of transmission failures" How may thousands of dollars did those failures cost? Probably enough to make a short OCI thrifty by comparison.
Key words, "my wife is tough on automatics"...let the operating conditions determine the OCI for all the fluids...all highway miles with a steady foot is very, very different than leadfoot in the city...
Originally Posted By: SOHCman
Originally Posted By: RamFan
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
It's funny how people always load their pants when someone doesn't do 100K on ~$30 of syn fluid, when this guy clearly said he has had "years of transmission failures" How may thousands of dollars did those failures cost? Probably enough to make a short OCI thrifty by comparison.
I can't see any driving condition where 5K tranny fluid changes aren't massive overkill...maybe using the vehicle purely for drag racing, but short of that, no way...
Originally Posted By: RamFan
Originally Posted By: Cujet
My wife is tough on automatics, with the constant, large throttle movements.
After years of transmission failures, I finally came to a solution:
Install a drain plug. Change oil and trans pan fluid every 5000 miles with Mobil 1 oil and Mobil 1 trans fluid. Problem solved.
Trans every 5k miles!!! Major overkill imo.
It's funny how people always load their pants when someone doesn't do 100K on ~$30 of syn fluid, when this guy clearly said he has had "years of transmission failures" How may thousands of dollars did those failures cost? Probably enough to make a short OCI thrifty by comparison.
I can't see any driving condition where 5K tranny fluid changes aren't massive overkill...maybe using the vehicle purely for drag racing, but short of that, no way...
Wow, I'm shocked by how much wrong information and myths are posted over and over in this thread. It's obvious that none of you have ever took apart a high mileage transmission before and don't know how things look down there. The only "crud" to dislodge is magnetically stuck to the transmission's magnetic magnets, usually on the bottom of the pan, other then that, the inside of the transmission is spotless, even if the oil wasn't changed for 100k+.
The only way this "crud" is getting loose is if you connect a high power flush machine and FORCE fluid through the transmission at crazy pressure. These machines aren't used anymore because they are not needed. A cooler line fluid exchange gets the job done without expensive machines.
Drain n fills won't dislodge anything. Cooler line fluid exchanges won't dislodge anything and is actually the best way to change ALL of the fluid in the transmission as you're able to keep the old fluid draining out and new fluid coming in until NEW fluid starts coming out of the return cooler line.
Drain n fills only remove small portions of the overall fluid in the transmission. Honda has a graph that shows how many drain n fills are needed to replace (or a proper way to say it would be, to mix new / old fluid) until you get as close to new fluid concentration as possible. The amount of drain n fills is over 6-7 if I remember correctly.
A cooler line fluid Exchange REMOVES old fluid while you put in new fluid. A drain n fill MIXES old fluid still on the tranny / radiator which instantly contaminated the new fluid coming in.
I suggest the op does a proper transmission fluid change to get ALL NEW fluid into the transmission. Another flush won't be needed for at least 60-100k. He'll probably sell the car by then.
The only way this "crud" is getting loose is if you connect a high power flush machine and FORCE fluid through the transmission at crazy pressure. These machines aren't used anymore because they are not needed. A cooler line fluid exchange gets the job done without expensive machines.
Drain n fills won't dislodge anything. Cooler line fluid exchanges won't dislodge anything and is actually the best way to change ALL of the fluid in the transmission as you're able to keep the old fluid draining out and new fluid coming in until NEW fluid starts coming out of the return cooler line.
Drain n fills only remove small portions of the overall fluid in the transmission. Honda has a graph that shows how many drain n fills are needed to replace (or a proper way to say it would be, to mix new / old fluid) until you get as close to new fluid concentration as possible. The amount of drain n fills is over 6-7 if I remember correctly.
A cooler line fluid Exchange REMOVES old fluid while you put in new fluid. A drain n fill MIXES old fluid still on the tranny / radiator which instantly contaminated the new fluid coming in.
I suggest the op does a proper transmission fluid change to get ALL NEW fluid into the transmission. Another flush won't be needed for at least 60-100k. He'll probably sell the car by then.
What do I do with the other end of the return line?
Leave it open or plug it?
Leave it open or plug it?
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