Or is it a good idea? When I say total change, I mean changing as much of the fluid as I can by removing the cooler line and have it going to a bucket while pouring in new ATF while the engine is running- after I drop pan and replace filter. No flush chemicals, additives or "force flush" machine will be used. Transmission is a 4T40 in a Olds Alero. So good idea or bad?
Is doing a complete ATF change a real bad idea?
- Thread starter CLeming
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As long as the fluid can be poured in at the same rate so that the pump isn't starved of fluid.I can't do this on mine ,It just wont flow in fast enough.I have to pump out about 3/4 of a gallon and then replace.
I think it's a great idea to do the full exchange. I would drop and clean the pan and change the filter also.
I recently had all this done on my Ford and it improved significantly. While researching the whole process, I discovered that what you described above was the recommended procedure (but with multiple steps to ensure it was done safely).
Dropping the pan is important to allow you to inspect everything more closely eg the magnet. If you find that the system was particularly dirty, you may want to consider doing another full exchange several thousand miles later as the new fluid may end up performing a lot of cleaning.
In that case, you may want to get some cheap ATF for this change, and then refill later with some higher quality full synthetic ATF.
And remember to buy the exact spec of ATF for your vehicle. Don't buy anything multi purpose.
I recently had all this done on my Ford and it improved significantly. While researching the whole process, I discovered that what you described above was the recommended procedure (but with multiple steps to ensure it was done safely).
Dropping the pan is important to allow you to inspect everything more closely eg the magnet. If you find that the system was particularly dirty, you may want to consider doing another full exchange several thousand miles later as the new fluid may end up performing a lot of cleaning.
In that case, you may want to get some cheap ATF for this change, and then refill later with some higher quality full synthetic ATF.
And remember to buy the exact spec of ATF for your vehicle. Don't buy anything multi purpose.
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A fluid flush is a poor idea I think, if the AT has lots of miles on it. A fluid exchange is probably a good idea.
It's a good idea if executed properly. Not too difficult, but can be a bit messy. I had the output tube flop out of the bucket when I was doing a Honda Accord. Not a huge amount of old ATF escaped, but still.
Amsoil ATF will work great in the 4T40 in the Alero. If your fluid is fairly shot, you will have a noticeable improvement with fresh fluid.
Amsoil ATF will work great in the 4T40 in the Alero. If your fluid is fairly shot, you will have a noticeable improvement with fresh fluid.
Originally Posted By: Eddie
A fluid flush is a poor idea I think, if the AT has lots of miles on it. A fluid exchange is probably a good idea.
A flush IS an exchange. Different names for the same thing. And yes I would recommend this service.
A fluid flush is a poor idea I think, if the AT has lots of miles on it. A fluid exchange is probably a good idea.
A flush IS an exchange. Different names for the same thing. And yes I would recommend this service.
I replaced the OEM transmission fluid on my 98 Camry @ 100k miles with Mobil 1 synthetic "multi purpose" formula. Tranny instantly started shifting MUCH better, esp in cooler weather. I did a second and 3rd drain n fill a few days and 100 miles apart. Shifted almost flawlessly. Couldn't feel the shifts half the time, esp the higher gears.
@ 160k i did 2 more regular drain n fills with M1 Synthetic tranny fluid (new formula now)
The Camry is now @ 210,00 miles and i swear it shifts just as smooth as it did when it had 45,000 miles on it. Tranny fluid is Pink as can be but i still plan to keep changing it @ 60k intervals to keep things clean and fresh and continue the amazing shift quality for as long as possible.
This time i'm going with Amsoil ATF, (again, a multi vehicle formula, which i also use in my 2007 Civic EX 5spd Auto with excellent results)
I might consider dropping the pan to finally clean the magnet after almost 15 years of service but with such good performance out of the transmission, i might keep doing regular drain n fills until the car is retired after 300k miles and replaced with something new
@ 160k i did 2 more regular drain n fills with M1 Synthetic tranny fluid (new formula now)
The Camry is now @ 210,00 miles and i swear it shifts just as smooth as it did when it had 45,000 miles on it. Tranny fluid is Pink as can be but i still plan to keep changing it @ 60k intervals to keep things clean and fresh and continue the amazing shift quality for as long as possible.
This time i'm going with Amsoil ATF, (again, a multi vehicle formula, which i also use in my 2007 Civic EX 5spd Auto with excellent results)
I might consider dropping the pan to finally clean the magnet after almost 15 years of service but with such good performance out of the transmission, i might keep doing regular drain n fills until the car is retired after 300k miles and replaced with something new
For what it's worth here is what I do.
drop the pan every 60,000 miles to change filter, every 30,000 miles I drain and replace the fluid 3 times. I run the car and the trans while up on stands for 10 minutes moving carefully through the gears.
Important on your first drain measure what has come out, record that volume for future reference, and replace with your new ATF. I'm getting 80% to 90% of the old atf depending on which vehicle I'm doing. to get into the high 90% you need to repeat 5 to 6 times. Since Dex-VI and MercV are supposed to be good for 100,000 miles then the old fluid left in has more life especially after being fortified by the new fluid.
That's my seat of the pants analysis!
drop the pan every 60,000 miles to change filter, every 30,000 miles I drain and replace the fluid 3 times. I run the car and the trans while up on stands for 10 minutes moving carefully through the gears.
Important on your first drain measure what has come out, record that volume for future reference, and replace with your new ATF. I'm getting 80% to 90% of the old atf depending on which vehicle I'm doing. to get into the high 90% you need to repeat 5 to 6 times. Since Dex-VI and MercV are supposed to be good for 100,000 miles then the old fluid left in has more life especially after being fortified by the new fluid.
That's my seat of the pants analysis!
Wow I spent $75 on the fluid for one exchange. How much are you spending to do 3 drains when really 1 would be fine?
I believe there are techniques for exchanging all the fluid which only use a quart or two more than the capacity. Essentially you let all the old fluid run out while adding and pushing it out with new fluid. When the fluid runs out fresh, you've gotten out virtually 100% of the old fluid.
No need to do 3 full drain and refills when doing regular changes. Doing a couple a few hundred miles apart might make sense if the transmission had been previously neglected.
I believe there are techniques for exchanging all the fluid which only use a quart or two more than the capacity. Essentially you let all the old fluid run out while adding and pushing it out with new fluid. When the fluid runs out fresh, you've gotten out virtually 100% of the old fluid.
No need to do 3 full drain and refills when doing regular changes. Doing a couple a few hundred miles apart might make sense if the transmission had been previously neglected.
Originally Posted By: exranger06
Originally Posted By: Eddie
A fluid flush is a poor idea I think, if the AT has lots of miles on it. A fluid exchange is probably a good idea.
A flush IS an exchange. Different names for the same thing. And yes I would recommend this service.
Not quite. Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it. In older transmissions, this can dislodge gunk without completely removing it and make things worse.
So sometimes a flush is different to an exchange.
I didn't want to do the work myself and went through many many garages asking them exactly what they did and received different names for the procedure and different explanations of what the procedure entailed.
At the end of the day, I decided it was best to make sure the pan was dropped so that all the gunk was removed and the filter could be changed before adding new fluid in an exchange procedure.
In my opinion, flushing is a bad idea whatever the state of the transmission. If the transmission is neglected, it needs gentle cleaning and more frequent change outs. Similar to how you would clean a neglected engine with more frequent OCI's. Dropping the pan helps you determine how bad things are. In my case, the was a carbon coating on the filter and presumably the pan, but nothing serious enough to require more than manufacturer recommended intervals going forward.
Originally Posted By: Eddie
A fluid flush is a poor idea I think, if the AT has lots of miles on it. A fluid exchange is probably a good idea.
A flush IS an exchange. Different names for the same thing. And yes I would recommend this service.
Not quite. Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it. In older transmissions, this can dislodge gunk without completely removing it and make things worse.
So sometimes a flush is different to an exchange.
I didn't want to do the work myself and went through many many garages asking them exactly what they did and received different names for the procedure and different explanations of what the procedure entailed.
At the end of the day, I decided it was best to make sure the pan was dropped so that all the gunk was removed and the filter could be changed before adding new fluid in an exchange procedure.
In my opinion, flushing is a bad idea whatever the state of the transmission. If the transmission is neglected, it needs gentle cleaning and more frequent change outs. Similar to how you would clean a neglected engine with more frequent OCI's. Dropping the pan helps you determine how bad things are. In my case, the was a carbon coating on the filter and presumably the pan, but nothing serious enough to require more than manufacturer recommended intervals going forward.
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Originally Posted By: rjacket
Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it.
I'm not calling you out here, but I've heard for years about these alleged "backwards flush" machines, yet I've never actually seen one, or talked to anyone who has actually seen one. All the ones I've been able to verify use the transmission's own pump to push out the old fluid while simultaneously pulling in the fresh...no extra pressure, no backwards flow.
Anyway, as far as the OP's question, my take is this:
Joe Six-Pack drives his car for years, towing his boat to the lake every weekend, driving through the mountains in July with his family and morbidly obese mother-in-law and their luggage for a week, etc. Never even THINKS about his transmission. One day it starts acting up: slipping, whining, shifting funny, whatever. It's almost time for his next oil change, so while he's at Jiffy Loob he mentions it to the "technician" who sells him on a fluid exchange. 3 weeks later, his neglected, abused transmission finally croaks. Since the last thing done was the flush, of COURSE that's what killed it, not the years of neglect.
Seems to me that if the fluid is all burnt and smelly the transmission is on its last legs and a fluid exchange at that point is too little, too late. If the fluid is relatively clean and pink, then there should be no reason not to flush it.
Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it.
I'm not calling you out here, but I've heard for years about these alleged "backwards flush" machines, yet I've never actually seen one, or talked to anyone who has actually seen one. All the ones I've been able to verify use the transmission's own pump to push out the old fluid while simultaneously pulling in the fresh...no extra pressure, no backwards flow.
Anyway, as far as the OP's question, my take is this:
Joe Six-Pack drives his car for years, towing his boat to the lake every weekend, driving through the mountains in July with his family and morbidly obese mother-in-law and their luggage for a week, etc. Never even THINKS about his transmission. One day it starts acting up: slipping, whining, shifting funny, whatever. It's almost time for his next oil change, so while he's at Jiffy Loob he mentions it to the "technician" who sells him on a fluid exchange. 3 weeks later, his neglected, abused transmission finally croaks. Since the last thing done was the flush, of COURSE that's what killed it, not the years of neglect.
Seems to me that if the fluid is all burnt and smelly the transmission is on its last legs and a fluid exchange at that point is too little, too late. If the fluid is relatively clean and pink, then there should be no reason not to flush it.
Originally Posted By: CLeming
Or is it a good idea? When I say total change, I mean changing as much of the fluid as I can by removing the cooler line and have it going to a bucket while pouring in new ATF while the engine is running- after I drop pan and replace filter. No flush chemicals, additives or "force flush" machine will be used. Transmission is a 4T40 in a Olds Alero. So good idea or bad?
There is no such thing as a force flush. The transmission has its own pump that pumps ATF when the engine is running. If the engine is off I doubt you could "force flush" much ATF past the pump.
New fluid in an AT is always a good idea unless you are pushing the vehicle into the garage. In that case you would be wasting your money.
Or is it a good idea? When I say total change, I mean changing as much of the fluid as I can by removing the cooler line and have it going to a bucket while pouring in new ATF while the engine is running- after I drop pan and replace filter. No flush chemicals, additives or "force flush" machine will be used. Transmission is a 4T40 in a Olds Alero. So good idea or bad?
There is no such thing as a force flush. The transmission has its own pump that pumps ATF when the engine is running. If the engine is off I doubt you could "force flush" much ATF past the pump.
New fluid in an AT is always a good idea unless you are pushing the vehicle into the garage. In that case you would be wasting your money.
Originally Posted By: RF Overlord
Originally Posted By: rjacket
Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it.
I'm not calling you out here, but I've heard for years about these alleged "backwards flush" machines, yet I've never actually seen one, or talked to anyone who has actually seen one. All the ones I've been able to verify use the transmission's own pump to push out the old fluid while simultaneously pulling in the fresh...no extra pressure, no backwards flow.
Anyway, as far as the OP's question, my take is this:
Joe Six-Pack drives his car for years, towing his boat to the lake every weekend, driving through the mountains in July with his family and morbidly obese mother-in-law and their luggage for a week, etc. Never even THINKS about his transmission. One day it starts acting up: slipping, whining, shifting funny, whatever. It's almost time for his next oil change, so while he's at Jiffy Loob he mentions it to the "technician" who sells him on a fluid exchange. 3 weeks later, his neglected, abused transmission finally croaks. Since the last thing done was the flush, of COURSE that's what killed it, not the years of neglect.
Seems to me that if the fluid is all burnt and smelly the transmission is on its last legs and a fluid exchange at that point is too little, too late. If the fluid is relatively clean and pink, then there should be no reason not to flush it.
You might be right about the machines, although I was quoted for the work supposedly with one of them.
The pink color is a dye. It is likely the fluid is past it's best if the fluid is no longer pink, but not necessarily the case.
One approach for the OP if he is worried would be just to drop the pan, clean the magnet, replace the filter, and only exchange what ATF he loses from the pan.
If the car accepts this, then several hundred miles later, perform a full fluid exchange without dropping the pan.
Originally Posted By: rjacket
Some garages / machines use pressure to exchange ie flush the fluid backwards, supposedly to clean it.
I'm not calling you out here, but I've heard for years about these alleged "backwards flush" machines, yet I've never actually seen one, or talked to anyone who has actually seen one. All the ones I've been able to verify use the transmission's own pump to push out the old fluid while simultaneously pulling in the fresh...no extra pressure, no backwards flow.
Anyway, as far as the OP's question, my take is this:
Joe Six-Pack drives his car for years, towing his boat to the lake every weekend, driving through the mountains in July with his family and morbidly obese mother-in-law and their luggage for a week, etc. Never even THINKS about his transmission. One day it starts acting up: slipping, whining, shifting funny, whatever. It's almost time for his next oil change, so while he's at Jiffy Loob he mentions it to the "technician" who sells him on a fluid exchange. 3 weeks later, his neglected, abused transmission finally croaks. Since the last thing done was the flush, of COURSE that's what killed it, not the years of neglect.
Seems to me that if the fluid is all burnt and smelly the transmission is on its last legs and a fluid exchange at that point is too little, too late. If the fluid is relatively clean and pink, then there should be no reason not to flush it.
You might be right about the machines, although I was quoted for the work supposedly with one of them.
The pink color is a dye. It is likely the fluid is past it's best if the fluid is no longer pink, but not necessarily the case.
One approach for the OP if he is worried would be just to drop the pan, clean the magnet, replace the filter, and only exchange what ATF he loses from the pan.
If the car accepts this, then several hundred miles later, perform a full fluid exchange without dropping the pan.
While I have never actually seen one of the reverse flush machines personally, there have been references to them in various literature. I have never cared enough to do any research because I did my own fluid exchanges, but I had occasion to talk to Abe Khalil (the Khalil of Eleftherakis and Khalil, the two engineers that did so much research on ATF and wrote so many great SAE white papers on the subject) spent a great deal of time condemning those machines and describing in detail the harm they did. So they exist, or at least existed. Maybe their faults led to their demise in the past few years.
I agree wit RF Overlord above about the "ATF change that kills transmissions" and rjacket about dropping the pan before doing a fluid exchange.
I will repeat my mantra yet again that dropping the pan for the first change is the most important pan drop because all the break-in and manufacturing contamination will be in there. Remember that 75 percent of the total lifetime contamination of an automatic will come in the first 5000 miles due to break in and manufacturing. Once that period is passed and the fluid filtered or changed, the contamination levels (mg/mile) drops massively.
I agree wit RF Overlord above about the "ATF change that kills transmissions" and rjacket about dropping the pan before doing a fluid exchange.
I will repeat my mantra yet again that dropping the pan for the first change is the most important pan drop because all the break-in and manufacturing contamination will be in there. Remember that 75 percent of the total lifetime contamination of an automatic will come in the first 5000 miles due to break in and manufacturing. Once that period is passed and the fluid filtered or changed, the contamination levels (mg/mile) drops massively.
Somebody else had another explanation. If the transmission has moderatr clogs in it and if the cleaner is too aggressive, it could dislodge larger chunks and could block critical passages which were not completely blocked before. I personally do not know if just exchanging the fluid adds so much cleaner to cause this kind of problem but it does sound feasible.
Originally Posted By: Vikas
Somebody else had another explanation. If the transmission has moderatr clogs in it and if the cleaner is too aggressive, it could dislodge larger chunks and could block critical passages which were not completely blocked before. I personally do not know if just exchanging the fluid adds so much cleaner to cause this kind of problem but it does sound feasible.
Which is why on a neglected transmission, you may want to only drop the pan and change the filter and therefore exchange the fluid partially.
Repeat at some interval until you are satisfied that gentle cleaning has taken place, then revert to full fluid exchanges.
Using cleaners and pressure on neglected transmissions seems to be a really bad idea. In one of the quotes I received, they refused to do a full exchange and only offered pan drops due to issues in the past.
I've exchanged my power steering fluid using the partial method, so that the new fluid helps to gently clean the system.
Somebody else had another explanation. If the transmission has moderatr clogs in it and if the cleaner is too aggressive, it could dislodge larger chunks and could block critical passages which were not completely blocked before. I personally do not know if just exchanging the fluid adds so much cleaner to cause this kind of problem but it does sound feasible.
Which is why on a neglected transmission, you may want to only drop the pan and change the filter and therefore exchange the fluid partially.
Repeat at some interval until you are satisfied that gentle cleaning has taken place, then revert to full fluid exchanges.
Using cleaners and pressure on neglected transmissions seems to be a really bad idea. In one of the quotes I received, they refused to do a full exchange and only offered pan drops due to issues in the past.
I've exchanged my power steering fluid using the partial method, so that the new fluid helps to gently clean the system.
I think its more due to shops not wanting to be on the hook for a transmission that might be on its way out.
Originally Posted By: Jim Allen
Originally Posted By: Donald
I think its more due to shops not wanting to be on the hook for a transmission that might be on its way out.
Bingo! A fluid exchange is of no harm (and great benefit) to a trans in good shape.
Agreed. Something about leaving old fluid in the trans bothers me.
I had a pan drop done followed by a flush on my 150K mile Explorer when I got it. The trans shifted exactly the same after the flush...a good thing. Maintenance history before that was vague, but I know it was the original trans and had never been opened up before.
My Ranger has had three flushes done in its life...112K miles and zero trans issues ever. Pan has never been off, fluid has almost 30K on it now and looks like it was poured in yesterday. I think the key to AT longevity is to start with 30K mile flushes early in the vehicle's life and keep up with them. This has worked very well for me.
When the trans in my roommate's Liberty started acting up in OD (180K miles, original fluid at the time), I did not hesistate to tell him to take it to the dealer for a flush. The flush helped with the issue immensely. It will still sometimes shudder in OD, but not nearly to the extent it did. Aamco had already started priming him for a rebuilt trans and wanted more money to do the flush with who knows what kind of fluid. The Jeep dealer didn't seem worried about it at all.
There are extreme cases where a full fluid change might be the death of an already ailing transmission, but at that point the trans is going to need to be replaced/rebuilt soon anyway.
Originally Posted By: Donald
I think its more due to shops not wanting to be on the hook for a transmission that might be on its way out.
Bingo! A fluid exchange is of no harm (and great benefit) to a trans in good shape.
Agreed. Something about leaving old fluid in the trans bothers me.
I had a pan drop done followed by a flush on my 150K mile Explorer when I got it. The trans shifted exactly the same after the flush...a good thing. Maintenance history before that was vague, but I know it was the original trans and had never been opened up before.
My Ranger has had three flushes done in its life...112K miles and zero trans issues ever. Pan has never been off, fluid has almost 30K on it now and looks like it was poured in yesterday. I think the key to AT longevity is to start with 30K mile flushes early in the vehicle's life and keep up with them. This has worked very well for me.
When the trans in my roommate's Liberty started acting up in OD (180K miles, original fluid at the time), I did not hesistate to tell him to take it to the dealer for a flush. The flush helped with the issue immensely. It will still sometimes shudder in OD, but not nearly to the extent it did. Aamco had already started priming him for a rebuilt trans and wanted more money to do the flush with who knows what kind of fluid. The Jeep dealer didn't seem worried about it at all.
There are extreme cases where a full fluid change might be the death of an already ailing transmission, but at that point the trans is going to need to be replaced/rebuilt soon anyway.
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Originally Posted By: Jim Allen
I will repeat my mantra yet again that dropping the pan for the first change is the most important pan drop because all the break-in and manufacturing contamination will be in there. Remember that 75 percent of the total lifetime contamination of an automatic will come in the first 5000 miles due to break in and manufacturing. Once that period is passed and the fluid filtered or changed, the contamination levels (mg/mile) drops massively.
By this logic, I assume you agree with an early pan drop and fill, crank and run until "new" comes through and bring level up to spec. I firmly believe in this as well, but have only done this when I purchased used vehicles, that is changing it as soon as I get the vehicle. The Corolla in my signature is my first new car. It is approaching 10,000 miles and I'd like to get rid of the factory fill. Toyota doesn't have it in their maintenance manual through 120,000 and that is where the maintenance schedule stops. I've got to locate a service manual to find the internal. The the system holds 6.9 qt so even at $6-8, you're talking about $75 not including the transmission gasket and filter, if it as the filter.
I will repeat my mantra yet again that dropping the pan for the first change is the most important pan drop because all the break-in and manufacturing contamination will be in there. Remember that 75 percent of the total lifetime contamination of an automatic will come in the first 5000 miles due to break in and manufacturing. Once that period is passed and the fluid filtered or changed, the contamination levels (mg/mile) drops massively.
By this logic, I assume you agree with an early pan drop and fill, crank and run until "new" comes through and bring level up to spec. I firmly believe in this as well, but have only done this when I purchased used vehicles, that is changing it as soon as I get the vehicle. The Corolla in my signature is my first new car. It is approaching 10,000 miles and I'd like to get rid of the factory fill. Toyota doesn't have it in their maintenance manual through 120,000 and that is where the maintenance schedule stops. I've got to locate a service manual to find the internal. The the system holds 6.9 qt so even at $6-8, you're talking about $75 not including the transmission gasket and filter, if it as the filter.
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