Changing ATF kills old transmissions???
- Thread starter j_mac
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Ewww...very very iffy topic.
I bought a car once that the tranny fluid was brown and there was rust on the dipstick.
I flushed it then drove it for a week then I dropped the pan and changed the filter. Never had a problem. I put 20000 miles on that car and then traded it.
I think you are better off changing the filter then not. Most old-school mechanics have a big problem with FLUSHING a transmission if it has not been maintained.
I don't think you can hurt it by dropping the pan and changing the filter. Of course cleaning all the gunk out of the bottom of the pan could not IMO hurt it.
I bought a car once that the tranny fluid was brown and there was rust on the dipstick.
I flushed it then drove it for a week then I dropped the pan and changed the filter. Never had a problem. I put 20000 miles on that car and then traded it.
I think you are better off changing the filter then not. Most old-school mechanics have a big problem with FLUSHING a transmission if it has not been maintained.
I don't think you can hurt it by dropping the pan and changing the filter. Of course cleaning all the gunk out of the bottom of the pan could not IMO hurt it.
I've heard it before.......that the detergents in the ATF will screw it up because it's cleaning the transmission out, but that's why there's a filter in the transmission pan.........however, old tales aside, I change the fluid and filter out anyway and I've never had that problem before. All I've ever seen is better shifting as a result of the fluid/filter change. My thing is that any new fresh fluid is better than any old and burnt fluid. If anything, the worst thing that could possibly happen from your fluid/filter change is the new filter got stopped up with stuff due to the detergents in the new fluid and you might need to swap the filter out again with another new one.......but once again I've never had that problem and I've bought plenty of vehicles with burnt or overly burnt transmission fluid and never had one transmission to go out. Luck and coincidence? I don't think so. I think this is an old wives tale.
I can't speak for anyone else, but whenever I buy a vehicle and the fluid is overly burnt, I generally buy the cheapest ATF I can get my hands on (usually a case from a distributor) and run it for a few thousand miles (10,000 max) and replace it with good, quality ATF. It's 2 fluid changes, but at this point, I have peace of mind knowing that I did what was necessary to clean the the transmission out and setting the transmission up for normal ATF fluid change intervals afterwards.
I can't speak for anyone else, but whenever I buy a vehicle and the fluid is overly burnt, I generally buy the cheapest ATF I can get my hands on (usually a case from a distributor) and run it for a few thousand miles (10,000 max) and replace it with good, quality ATF. It's 2 fluid changes, but at this point, I have peace of mind knowing that I did what was necessary to clean the the transmission out and setting the transmission up for normal ATF fluid change intervals afterwards.
I think how this came up is if the transmission is close to failing, the new friction modification package may make it slip bad enough to fail quick. If it is that bad, it was on its last leg anyway, however, it just might've lasted a few thousand more.
ok here is the deal
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
Originally Posted By: electrolover
ok here is the deal
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
ok here is the deal
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
I have heard that for years.But I'll say I have handled literally thousands of transmission filter changes and fliud exchange(so call it a flush) using a BG machine.I have had automatica that had hard seals and morning sickness,won't go until heat swells the seals that a fliud exchange with BG seal additive help immensely.Not cured but helped.They still needed a overhaul but it bought the owners a few more miles.I never had one just fail and be able to say it was because of new fliud.
MY local Pennzoil oil change place will not flush an AT with over 100,000 miles unless receipts are avail to show it has been done before. They turn away good money because " too many At failures when flushed for the first time at over 100K miles" Some manufactures recommend never to flush-Honda and or Subaru, I think. Plug drain and refill is my way to go.
Also keep in mind that on some trannies that are computer controlled such as the Chrysler 4 speeds, sometimes a fluid change will result in poor operation for awhile until the computer/tranny "relearn" the new fluid characteristics. At least, that's what mechanics have told me.
Wishing everyone a great upcoming new year.
Wishing everyone a great upcoming new year.
Originally Posted By: NHHEMI
Originally Posted By: electrolover
ok here is the deal
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
I agree as well. I think this rumor of changing transmission fluid will kill an old tranny comes from the fact that most people will only change there tranny fluid once something is going wrong. If you change the tranny fluid for the first time when you are having problems and the tranny dies a lot of people will blame the tranny fluid. As a result the rumor has developed that new ATF will kill an old tranny that has not been maintained. The real problem is that people don't maintain there cars properly by changing the ATF regularly.
The way I look at it is if you change the fluid and it goes, it probably would have gone anyways. If you change it and it works, your just maintaining your vehicle and giving yourself tens of thousands of extra miles to drive.
Originally Posted By: electrolover
ok here is the deal
people dont all change the trans fluid so grit from the clutch faces gets in the fluid. this makes for more friction and then even more grit, and so on until the grit in the fluid is the only thing holding the clutches from slipping. they sell the car and the next guy has a flush done and bam slipping tranny. and he blames the flush.
if your car is in good shape i say dont worry about a flush hurting it. if your fluid is black it might go out on you but it was going out anyway.
so my opinion is dont hesitate to do a flush or fluid filter change on a transmission. and if it goes out on you after its because it was already on its way you just sped it up a week or so, but if its in good shape it will stay that way.
I agree as well. I think this rumor of changing transmission fluid will kill an old tranny comes from the fact that most people will only change there tranny fluid once something is going wrong. If you change the tranny fluid for the first time when you are having problems and the tranny dies a lot of people will blame the tranny fluid. As a result the rumor has developed that new ATF will kill an old tranny that has not been maintained. The real problem is that people don't maintain there cars properly by changing the ATF regularly.
The way I look at it is if you change the fluid and it goes, it probably would have gone anyways. If you change it and it works, your just maintaining your vehicle and giving yourself tens of thousands of extra miles to drive.
Just brought home a cutlass ciera.
Has a tranny leak from the cooling line, am working on that.
140k miles, had the goofy cheap rubber pan gasket you get with the discount store filter kit. So it was changed at least once.
Brown fluid, grey with silt. Was probably run so low on fluid it started slipping then topped off.
I changed the filter, fluid, gasket, and put an adjustable modulator on it. Cranked the screw on the modulator to make more pressure on the clutches. Put in a little bars leaks tranny fluid conditioner, STP like syrup to thicken it up a little.
This trans was slipping like crazy once it left 1st gear. Had to really nurse it.
Now it holds solid, or, dare I say it, better than new. (Programmed to be slushy to please old people.)
Though old fluid has some grey stuff in it it also loses viscosity and bleeds around the o-rings. I would strongly assume many trannies have problems start in the valve bodies, not being able to apply the appropriate pressure to the clutches, which then wears them out. It takes time though so if you notice tranny issues for heavens sake handle them early! I saved a trans that many would say was pretty far gone and a shop probably would have said "rebuild"!
If you really want to band aid an old trans use type F where dexron is called for, it slips less. But my generic "dex/M" is doing quite nicely.
Has a tranny leak from the cooling line, am working on that.
140k miles, had the goofy cheap rubber pan gasket you get with the discount store filter kit. So it was changed at least once.
Brown fluid, grey with silt. Was probably run so low on fluid it started slipping then topped off.
I changed the filter, fluid, gasket, and put an adjustable modulator on it. Cranked the screw on the modulator to make more pressure on the clutches. Put in a little bars leaks tranny fluid conditioner, STP like syrup to thicken it up a little.
This trans was slipping like crazy once it left 1st gear. Had to really nurse it.
Now it holds solid, or, dare I say it, better than new. (Programmed to be slushy to please old people.)
Though old fluid has some grey stuff in it it also loses viscosity and bleeds around the o-rings. I would strongly assume many trannies have problems start in the valve bodies, not being able to apply the appropriate pressure to the clutches, which then wears them out. It takes time though so if you notice tranny issues for heavens sake handle them early! I saved a trans that many would say was pretty far gone and a shop probably would have said "rebuild"!
If you really want to band aid an old trans use type F where dexron is called for, it slips less. But my generic "dex/M" is doing quite nicely.
If you only did a flush, (no filter change) you run the risk of clogging the already half clogged (probably) filter. So if you do not know the condition of the filter it needs to be changed as part of the flush.
Originally Posted By: j_mac
I had a guy who works for a transmission shop tell me that an old transmission that might be on its last leg is more likely to go ahead and expire soon after an ATF fluid change.
What do you guys think?
Its the most overhyped bee-ess on the internet.
Any transmission on its last leg will expire on its own. Its not going to care if the fluid is new or old.
In my experience, new ATF ALWAYS increase the life of a transmission.
I had a guy who works for a transmission shop tell me that an old transmission that might be on its last leg is more likely to go ahead and expire soon after an ATF fluid change.
What do you guys think?
Its the most overhyped bee-ess on the internet.
Any transmission on its last leg will expire on its own. Its not going to care if the fluid is new or old.
In my experience, new ATF ALWAYS increase the life of a transmission.
Originally Posted By: unDummy
Originally Posted By: j_mac
I had a guy who works for a transmission shop tell me that an old transmission that might be on its last leg is more likely to go ahead and expire soon after an ATF fluid change.
What do you guys think?
Its the most overhyped bee-ess on the internet.
Any transmission on its last leg will expire on its own. Its not going to care if the fluid is new or old.
In my experience, new ATF ALWAYS increase the life of a transmission.
Originally Posted By: j_mac
I had a guy who works for a transmission shop tell me that an old transmission that might be on its last leg is more likely to go ahead and expire soon after an ATF fluid change.
What do you guys think?
Its the most overhyped bee-ess on the internet.
Any transmission on its last leg will expire on its own. Its not going to care if the fluid is new or old.
In my experience, new ATF ALWAYS increase the life of a transmission.
What is a transmission flush?
Sometimes it is a fluid exchange where a pair of reservoirs are connected into the cooling supply and return lines, and the transmission's own pump puts old fluid into one reservoir and pushes new fluid into the transmission sump.
Here is one such machine:
http://www.asedeals.com/ttech_fluid_exchanger.html
Sometimes it is a pressure flush where the flush machine is connected to the transmission internal parts and new fluid is pumped through the transmission.
Here is one such machine:
http://transaction25.com/html/video.html
I've done many manual versions of the fluid exchange where I pump out a quart or two, stop the engine, replace the new fluid into the sump, pump again, etc. All the reasons listed above for a transmission failing soon after a fluid replacement sound reasonable to me, and the shop guys do not want to be caught in a bind where they do maintenance (not repairs) on a failing transmission, it does indeed fail, and they get the blame and are expected to replace the transmission for free.
Sometimes it is a fluid exchange where a pair of reservoirs are connected into the cooling supply and return lines, and the transmission's own pump puts old fluid into one reservoir and pushes new fluid into the transmission sump.
Here is one such machine:
http://www.asedeals.com/ttech_fluid_exchanger.html
Sometimes it is a pressure flush where the flush machine is connected to the transmission internal parts and new fluid is pumped through the transmission.
Here is one such machine:
http://transaction25.com/html/video.html
I've done many manual versions of the fluid exchange where I pump out a quart or two, stop the engine, replace the new fluid into the sump, pump again, etc. All the reasons listed above for a transmission failing soon after a fluid replacement sound reasonable to me, and the shop guys do not want to be caught in a bind where they do maintenance (not repairs) on a failing transmission, it does indeed fail, and they get the blame and are expected to replace the transmission for free.
That has been the story since before flush machines. The story goes like this,I bought a car and years later when the trans oil was black I brought it to a shop and had them change the oil. A year later the trans quit working. So new oil kills the trans ,not the 3 years of running the trans on dirty oil. You have to look at what happenes to cause a failure, parts breaking= poor quality, wearing out early=usually bad oil. Most things have the quality CAD designed out of them.
Here's another scenario:
Joe Happy Car-owner buys a new car. Manufacturer says the transaxle has "lifetime" fluid (or has a change interval of 150,000 miles or some other malarkey) so Joe thinks "Hey, cool!" and never thinks about his transaxle again. 6 years and 137,000 miles later, Joe trades "Bessie" in for a new car. Now, along comes Bill Car-buyer who can't afford a brand-new car, so he buys Joe's creampuff that has had all the "required" maintenance done, with paperwork to prove it. 6 months later, the transaxle in Bill's pride-and-joy is fubar and he gets told it'll be $2500 to fix it. So now, of course, Ford (or whoever) is junk.
So who's REALLY at fault here? I blame the manufacturers for playing the "keeping up with the Joneses" game with each other in claiming longer and longer intervals between regular maintenance. If Joe had just had the fluid changed ONCE, then Bill would prolly still be riding around in the breeze.
Joe Happy Car-owner buys a new car. Manufacturer says the transaxle has "lifetime" fluid (or has a change interval of 150,000 miles or some other malarkey) so Joe thinks "Hey, cool!" and never thinks about his transaxle again. 6 years and 137,000 miles later, Joe trades "Bessie" in for a new car. Now, along comes Bill Car-buyer who can't afford a brand-new car, so he buys Joe's creampuff that has had all the "required" maintenance done, with paperwork to prove it. 6 months later, the transaxle in Bill's pride-and-joy is fubar and he gets told it'll be $2500 to fix it. So now, of course, Ford (or whoever) is junk.
So who's REALLY at fault here? I blame the manufacturers for playing the "keeping up with the Joneses" game with each other in claiming longer and longer intervals between regular maintenance. If Joe had just had the fluid changed ONCE, then Bill would prolly still be riding around in the breeze.
Originally Posted By: Ken2
What is a transmission flush?
Sometimes it is a fluid exchange where a pair of reservoirs are connected into the cooling supply and return lines, and the transmission's own pump puts old fluid into one reservoir and pushes new fluid into the transmission sump.
Here is one such machine:
http://www.asedeals.com/ttech_fluid_exchanger.html
Sometimes it is a pressure flush where the flush machine is connected to the transmission internal parts and new fluid is pumped through the transmission.
Here is one such machine:
http://transaction25.com/html/video.html
I've done many manual versions of the fluid exchange where I pump out a quart or two, stop the engine, replace the new fluid into the sump, pump again, etc. All the reasons listed above for a transmission failing soon after a fluid replacement sound reasonable to me, and the shop guys do not want to be caught in a bind where they do maintenance (not repairs) on a failing transmission, it does indeed fail, and they get the blame and are expected to replace the transmission for free.
Ken - you are kind of misleading the viewers of this forum by mentioning a "pressure flush". In reality there is no such thing. The URL you point to is pure hype. In ANY flush its the transmissions own pump that pushes new ATF though the transmission. People need to understand that. It comes down to what about the fluid in the pan, and mixing of old and new ATF. You basically have 4 options: 1) drain old fluid in pan via drain plug then do flush 2) drop pan, then do flush 3) push old fluid out cooler line until you see bubbles in clear tubing then do flush 4) do a plain flush with say 4 extra QTs of ATF and any mixing will be taken care of.
What is a transmission flush?
Sometimes it is a fluid exchange where a pair of reservoirs are connected into the cooling supply and return lines, and the transmission's own pump puts old fluid into one reservoir and pushes new fluid into the transmission sump.
Here is one such machine:
http://www.asedeals.com/ttech_fluid_exchanger.html
Sometimes it is a pressure flush where the flush machine is connected to the transmission internal parts and new fluid is pumped through the transmission.
Here is one such machine:
http://transaction25.com/html/video.html
I've done many manual versions of the fluid exchange where I pump out a quart or two, stop the engine, replace the new fluid into the sump, pump again, etc. All the reasons listed above for a transmission failing soon after a fluid replacement sound reasonable to me, and the shop guys do not want to be caught in a bind where they do maintenance (not repairs) on a failing transmission, it does indeed fail, and they get the blame and are expected to replace the transmission for free.
Ken - you are kind of misleading the viewers of this forum by mentioning a "pressure flush". In reality there is no such thing. The URL you point to is pure hype. In ANY flush its the transmissions own pump that pushes new ATF though the transmission. People need to understand that. It comes down to what about the fluid in the pan, and mixing of old and new ATF. You basically have 4 options: 1) drain old fluid in pan via drain plug then do flush 2) drop pan, then do flush 3) push old fluid out cooler line until you see bubbles in clear tubing then do flush 4) do a plain flush with say 4 extra QTs of ATF and any mixing will be taken care of.
a flush really isnt a flush
i have done many trans fluid exchanges with a wynns machine
it just matches whats coming out of the line with new fluid on the return line. the transmission pump does most of the work.
i always speed it up on fords by putting it in neutral and holding it to 2k rpms. the fords pump lower volume than others
i think you can do the same thing in your driveway with some hoses and a funnel
i have done many trans fluid exchanges with a wynns machine
it just matches whats coming out of the line with new fluid on the return line. the transmission pump does most of the work.
i always speed it up on fords by putting it in neutral and holding it to 2k rpms. the fords pump lower volume than others
i think you can do the same thing in your driveway with some hoses and a funnel
I really don't think a fluid change with the correct fluid can hurt a transmission. If a transmission is already dying, how are you going to know when it is going to fail completely? I think for a lot of people, a fluid change is a last ditch effort to get a transmission to last a little while longer...probably because they didn't maintain it before. Once a transmission is in really bad shape though, a fluid change won't do anything. Then when the car leaves them stranded, they want to blame the place that flushed the fluid.
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