COMMENTS – reasons to change the TRANS ATF regularly
12-31-2013, 08:43 PM
#1
Burning Brakes
Thread Starter
COMMENTS – reasons to change the TRANS ATF regularly
Regularly changing the transmission ATF (automatic transmission fluid) will prevent buildup of wear material particles inside the transmission. These particles create a very abrasive slurry with the ATF, which will eventually damage the transmission. These particles wear the solenoids and their corresponding bores, causing them to leak, and also clog the solenoid filter screens.
The RDX transmission MAGNETS can only remove magnetic metals particles. Some of the remaining non-magnetic particles are not removed by the RDX transmission FILTERS, because the filters are not *fine* enough. And even the additional aftermarket external filter that I added into the transmission cooler line, on my own RDX, does not remove all wear particles. In a given trans fluid pressure control cycle, only part of the ATF is diverted through the trans cooler circuit. Only by removing some of the ATF by draining, will excess wear particles be removed from the transmission.
Plus, early model Honda/ Acura transmissions had replaceable trans filters, and removable trans bottom pans with removable pump screens and magnets in the pan. Your RDX transmission has the same magnets, filters, and pump screen – but none of these can be replaced. Is your RDX trans that much better than a ’95 Accord trans? Only time and 300K miles will tell.
This post shows pictures of what can happen if the transmission ATF fluid is not changed as required.
Apologies to those whose pictures I have borrowed in order to illustrate this post. I hope that the original posters of those pictures will not object.
HOW OFTEN TO CHANGE THE TRANS ATF?
The 2009 RDX owner manual suggests changing the trans ATF at 60K miles for severe service. I do not know when the MID (maintenance indicator display) would normally report a #3 request to change the trans fluid. I assume that the ATF itself will last for the period reported by the MID, but I also believe that too much wear material will build up inside the trans during that same period. Decide for yourself, based on the pictures in this post – but I have chosen to change the ATF in my own RDX at shorter intervals.
However, some gen-two RDX owners have posted on this forum, that their MID requested a transmission ATF change at about 30K miles.
https://acurazine.com/forums/showthread.php?t=887162
I wonder if the gen-ONE RDX trans is really *better* than the gen-TWO trans, or if Honda has decided that the gen-TWO trans fluid should be changed more frequently, for reliability.
Also, you might consider ATF replacement intervals based on service and time, rather than just on miles. Driving 100 miles on the freeway may only require 10 transmission shifts. But driving 100 miles in heavy city traffic, with a traffic light every 1-miles or less, may require as many as one thousand (1K) shifts. There would be 4-shifts down to stop, and 4-shifts up when leaving the lights, plus shifts as you slow for those people who don’t know how to drive (not like you of course).
A NOTE ABOUT THE PICTURES IN THIS POST
There are limited pics from the RDX transmission, because I do not have access to a disassembled RDX transmission. However, all of the Honda/ Acura transmissions built in the past 15 years or so are very similar functionally, and similar in design. We can only hope that design changes to the later transmissions has improved their reliability over the early trans, because Honda has lost several class-action law suits concerning their early transmissions which failed in service, during the warranty period.
THE MAGNETIC DRAIN PLUG
The magnet only attracts magnetic material, that is, metallic material. But the majority of the clutch material will not be captured by the drain plug, because clutch material is not magnetic.
However, some clutch material will be captured by the drain plug magnet, because of the chemical interaction between the clutch material and the magnetic wear material inside the transmission, binding them together. I am not a chemist, so I cannot explain this phenomenon, but it is generally accepted as occurring.
Note that the RDX drain plug has magnetic poles on the *sides* of the cylindrical magnet. That provides more area to attract magnetic material. Note that the delSol Honda trans drain plug has the magnetic poles on the ends of the cylindrical magnet. So only the very end/ tip of the magnet can attract (less) material.
PICTURES OF THE MAGNETIC DRAIN PLUG
As seen in the pictures below, a significant amount of wear material accumulates on the drain plug. It is not practical to compare your own drain plug against another vehicle. Different operating conditions just make that impossible. That is another reason to consider your own vehicle operating conditions when deciding when to change the ATF, rather than just a specific number of miles.
I will state that the drain plug in my own RDX, when removed for the first time at 8K miles, had twice the amount of wear material as shown in the picture below with the heaviest deposits. My drain plug could not *hold* any more material. There was a sort of *extension* on the end of the magnet, that fell off when the plug was removed. If I had waited until 30K miles to perform the first ATF change, any additional wear material not attached to the magnet, would have been circulating inside the trans.
MAGNETS INSIDE THE TRANSMISSION
There are magnets inside the RDX transmission. These magnets cannot be removed and cleaned, unless the transmission is disassembled. So what happens when these magnets reach the saturation point, and cannot capture any more material?
The pictures of the Honda delSol transmission internal magnet, is from a disassembled transmission.
http://honda-tech.com/showthread.php?t=2762323
TRANSMISSION ATF PUMP STRAINER/ FILTER
There is a strainer/ filter on the intake of the RDX transmission oil (ATF) pump. Honda calls this a strainer because it only *filters* very large (relative) particles, as evidenced by the amount of particles which appear on the drain plug magnet. The RDX pump filter cannot be replaced – its located inside the trans cases. Do you think that it cannot clog/ plug up? See the links just below in this same section.
The RDX pump strainer/ filter is equivalent to the replaceable similar filter in the oil pan of my Chevy transmission. My Chevy transmission oil pan is removable, so that the pump filter can be replaced. And the Chevy trans filter is much more than a simple strainer – it filters to 60 microns, relative to the Purolator Pure One RDX oil filter, which filters to 40 microns (as stated on the filter packaging).
Early Honda transmissions had a removable pan, and the strainer can be removed and cleaned or replaced. The following link reports a plugged gen-ONE 1996 TL trans strainer and shifting problems, *cured* by cleaning the strainer:
https://acurazine.com/forums/showthread.php?t=575994
Here is another link to removal of the trans strainer for a 2.5 TL, which shows just how much larger junk can accumulate on the strainer. Don’t you wonder why the paper filter is not removing that stuff?
https://acurazine.com/forums/showthread.php?t=684453
Here is a link with pics showing the location of the TL trans pan and strainer. Simply unbolt the pan, remove, then unbolt the strainer. Why couldn’t the RDX trans be like this?
https://acurazine.com/forums/showthread.php?t=591042
----eof
The RDX transmission MAGNETS can only remove magnetic metals particles. Some of the remaining non-magnetic particles are not removed by the RDX transmission FILTERS, because the filters are not *fine* enough. And even the additional aftermarket external filter that I added into the transmission cooler line, on my own RDX, does not remove all wear particles. In a given trans fluid pressure control cycle, only part of the ATF is diverted through the trans cooler circuit. Only by removing some of the ATF by draining, will excess wear particles be removed from the transmission.
Plus, early model Honda/ Acura transmissions had replaceable trans filters, and removable trans bottom pans with removable pump screens and magnets in the pan. Your RDX transmission has the same magnets, filters, and pump screen – but none of these can be replaced. Is your RDX trans that much better than a ’95 Accord trans? Only time and 300K miles will tell.
This post shows pictures of what can happen if the transmission ATF fluid is not changed as required.
Apologies to those whose pictures I have borrowed in order to illustrate this post. I hope that the original posters of those pictures will not object.
HOW OFTEN TO CHANGE THE TRANS ATF?
The 2009 RDX owner manual suggests changing the trans ATF at 60K miles for severe service. I do not know when the MID (maintenance indicator display) would normally report a #3 request to change the trans fluid. I assume that the ATF itself will last for the period reported by the MID, but I also believe that too much wear material will build up inside the trans during that same period. Decide for yourself, based on the pictures in this post – but I have chosen to change the ATF in my own RDX at shorter intervals.
However, some gen-two RDX owners have posted on this forum, that their MID requested a transmission ATF change at about 30K miles.
https://acurazine.com/forums/showthread.php?t=887162
I wonder if the gen-ONE RDX trans is really *better* than the gen-TWO trans, or if Honda has decided that the gen-TWO trans fluid should be changed more frequently, for reliability.
Also, you might consider ATF replacement intervals based on service and time, rather than just on miles. Driving 100 miles on the freeway may only require 10 transmission shifts. But driving 100 miles in heavy city traffic, with a traffic light every 1-miles or less, may require as many as one thousand (1K) shifts. There would be 4-shifts down to stop, and 4-shifts up when leaving the lights, plus shifts as you slow for those people who don’t know how to drive (not like you of course).
A NOTE ABOUT THE PICTURES IN THIS POST
There are limited pics from the RDX transmission, because I do not have access to a disassembled RDX transmission. However, all of the Honda/ Acura transmissions built in the past 15 years or so are very similar functionally, and similar in design. We can only hope that design changes to the later transmissions has improved their reliability over the early trans, because Honda has lost several class-action law suits concerning their early transmissions which failed in service, during the warranty period.
THE MAGNETIC DRAIN PLUG
The magnet only attracts magnetic material, that is, metallic material. But the majority of the clutch material will not be captured by the drain plug, because clutch material is not magnetic.
However, some clutch material will be captured by the drain plug magnet, because of the chemical interaction between the clutch material and the magnetic wear material inside the transmission, binding them together. I am not a chemist, so I cannot explain this phenomenon, but it is generally accepted as occurring.
Note that the RDX drain plug has magnetic poles on the *sides* of the cylindrical magnet. That provides more area to attract magnetic material. Note that the delSol Honda trans drain plug has the magnetic poles on the ends of the cylindrical magnet. So only the very end/ tip of the magnet can attract (less) material.
PICTURES OF THE MAGNETIC DRAIN PLUG
As seen in the pictures below, a significant amount of wear material accumulates on the drain plug. It is not practical to compare your own drain plug against another vehicle. Different operating conditions just make that impossible. That is another reason to consider your own vehicle operating conditions when deciding when to change the ATF, rather than just a specific number of miles.
I will state that the drain plug in my own RDX, when removed for the first time at 8K miles, had twice the amount of wear material as shown in the picture below with the heaviest deposits. My drain plug could not *hold* any more material. There was a sort of *extension* on the end of the magnet, that fell off when the plug was removed. If I had waited until 30K miles to perform the first ATF change, any additional wear material not attached to the magnet, would have been circulating inside the trans.
MAGNETS INSIDE THE TRANSMISSION
There are magnets inside the RDX transmission. These magnets cannot be removed and cleaned, unless the transmission is disassembled. So what happens when these magnets reach the saturation point, and cannot capture any more material?
The pictures of the Honda delSol transmission internal magnet, is from a disassembled transmission.
http://honda-tech.com/showthread.php?t=2762323
TRANSMISSION ATF PUMP STRAINER/ FILTER
There is a strainer/ filter on the intake of the RDX transmission oil (ATF) pump. Honda calls this a strainer because it only *filters* very large (relative) particles, as evidenced by the amount of particles which appear on the drain plug magnet. The RDX pump filter cannot be replaced – its located inside the trans cases. Do you think that it cannot clog/ plug up? See the links just below in this same section.
The RDX pump strainer/ filter is equivalent to the replaceable similar filter in the oil pan of my Chevy transmission. My Chevy transmission oil pan is removable, so that the pump filter can be replaced. And the Chevy trans filter is much more than a simple strainer – it filters to 60 microns, relative to the Purolator Pure One RDX oil filter, which filters to 40 microns (as stated on the filter packaging).
Early Honda transmissions had a removable pan, and the strainer can be removed and cleaned or replaced. The following link reports a plugged gen-ONE 1996 TL trans strainer and shifting problems, *cured* by cleaning the strainer:
https://acurazine.com/forums/showthread.php?t=575994
Here is another link to removal of the trans strainer for a 2.5 TL, which shows just how much larger junk can accumulate on the strainer. Don’t you wonder why the paper filter is not removing that stuff?
https://acurazine.com/forums/showthread.php?t=684453
Here is a link with pics showing the location of the TL trans pan and strainer. Simply unbolt the pan, remove, then unbolt the strainer. Why couldn’t the RDX trans be like this?
https://acurazine.com/forums/showthread.php?t=591042
----eof
Last edited by dcmodels; 12-31-2013 at 08:47 PM.
12-31-2013, 08:52 PM
#2
Burning Brakes
Thread Starter
CONTINUED:
PAPER FILTER INSIDE THE TRANSMISSION
There is a paper filter inside the RDX transmission, on the ATF cooler return line hose. That filter cannot be removed and replaced, unless the trans is disassembled and rebuilt. Early Honda/ Acura transmissions did have an external replaceable paper filter, as shown in the pictures below.
Now, consider how much material is on the TL transmission paper filter, which is replaceable. And how much additional material is on the various TL magnetic drain plugs. Neither the drain plug magnet, nor the internal magnets, nor the paper filter, nor the ATF pump strainer, has captured all of the wear material inside the transmission.
The RDX trans paper filter, is similar in size and construction to the TL paper filter in the pics below. The RDX paper filter has a spring loaded by-pass valve. So once the RDX paper filter becomes fully loaded, it will no longer be filtering anything.
And how soon will the RDX paper filter become clogged? Well, the person who posted the pic of the paper TL filter says that is <100K miles. Do you want your RDX trans to last beyond 100K miles?
MESH SCREENS INSIDE THE TRANSMISSION
There are metal mesh screens inside the RDX transmission. They can be removed and cleaned, by removing the externally accessible clutch control solenoids. There are many threads on the TL section of this forum, and threads on other Honda forums, concerning removal and cleaning of the screens and the solenoids themselves (because the solenoids wear and eventually fail).
I hope that the pictures below, show that these internal transmission screens can clog, despite the drain plug magnet, the internal magnets, the ATF pump filter/ strainer, and the internal paper filter.
Also, any *extra* unfiltered wear material circulating inside the transmission, is wearing away at the surface of the fluid pressure control solenoids and their bores, as well as clogging any internal screens.
WHAT CAN YOU DO TO HELP YOUR TRANS LAST LONGER?
There are three basic things that you can do to decrease and limit wear to the internals of your RDX transmission:
Ø Change the ATF fluid early and at shorter intervals than *required*, based upon your own service conditions. In particular, consider why the gen-Two RDX MID reports a shorter trans drain interval, than the gen-One RDX MID.
Ø Install an external replaceable magnetic/ paper filter in the transmission cooler line
Ø Clean the pressure control solenoid screens at intervals.
You do have some control over how long your RDX transmission will last before requiring replacement.
----eof
PAPER FILTER INSIDE THE TRANSMISSION
There is a paper filter inside the RDX transmission, on the ATF cooler return line hose. That filter cannot be removed and replaced, unless the trans is disassembled and rebuilt. Early Honda/ Acura transmissions did have an external replaceable paper filter, as shown in the pictures below.
Now, consider how much material is on the TL transmission paper filter, which is replaceable. And how much additional material is on the various TL magnetic drain plugs. Neither the drain plug magnet, nor the internal magnets, nor the paper filter, nor the ATF pump strainer, has captured all of the wear material inside the transmission.
The RDX trans paper filter, is similar in size and construction to the TL paper filter in the pics below. The RDX paper filter has a spring loaded by-pass valve. So once the RDX paper filter becomes fully loaded, it will no longer be filtering anything.
And how soon will the RDX paper filter become clogged? Well, the person who posted the pic of the paper TL filter says that is <100K miles. Do you want your RDX trans to last beyond 100K miles?
MESH SCREENS INSIDE THE TRANSMISSION
There are metal mesh screens inside the RDX transmission. They can be removed and cleaned, by removing the externally accessible clutch control solenoids. There are many threads on the TL section of this forum, and threads on other Honda forums, concerning removal and cleaning of the screens and the solenoids themselves (because the solenoids wear and eventually fail).
I hope that the pictures below, show that these internal transmission screens can clog, despite the drain plug magnet, the internal magnets, the ATF pump filter/ strainer, and the internal paper filter.
Also, any *extra* unfiltered wear material circulating inside the transmission, is wearing away at the surface of the fluid pressure control solenoids and their bores, as well as clogging any internal screens.
WHAT CAN YOU DO TO HELP YOUR TRANS LAST LONGER?
There are three basic things that you can do to decrease and limit wear to the internals of your RDX transmission:
Ø Change the ATF fluid early and at shorter intervals than *required*, based upon your own service conditions. In particular, consider why the gen-Two RDX MID reports a shorter trans drain interval, than the gen-One RDX MID.
Ø Install an external replaceable magnetic/ paper filter in the transmission cooler line
Ø Clean the pressure control solenoid screens at intervals.
You do have some control over how long your RDX transmission will last before requiring replacement.
----eof
12-31-2013, 10:21 PM
#3
I change 3 quarts every other oil change. I think that may be good. Thats what I was told by a Transmission guy said he did on this Chevy. I figure a good Chevy trans must be around a 02 cl trans kinda same level. Oh yeah I have 248,000 on an Acured "Fixed" transmission. Very smooth.
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