Why do transmissions fail after changing the fluid?
- Thread starter greencrew
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MIke you are right aout not all places replaceing the filter. I actualy called around just to see what each place in my city wanted. I specificly asked them if the filter was replaced with the flush. Most said "NO". The trany shop I called said that they always change the filter and they had the best price! You know people have to take an active role in their vechiles maintence. You can either do it yourself and learn something in the process or you must ask alot of question. No matter wich road you choose your vechiles health is no different then your own. No one is going to care more about your vechile then you do. I am a little bit of a snop at time in reguards to cars. I still expect every man to be able to hunt, build a fire in the wilderness and know the principals that govern an cars operation. I do not expect every guy to be a mechanic. I hate to see people get taken advantage of because they do not understand how a car works!
I would not add anything to it myself. Just change it out if that what you want to do. Just be sure that when you do change it the vehicle is a normal temps. Drain after its been driven for some time, that way any contaminants will be in suspension.
No, only reason to even change is to remove metal particles, I've seen vehicles go 200k+ miles on the original fluid. if syncros feel worn there are other fluids you can try, though syncromesh is one of the best.
Some vehicles have an external transmission filter and a drain hole, such as my 2003 Subaru.
Interesting that you should bring up the external filter on the Subaru.
I'm in somewhat of a heated debate over at http://forums.nasioc.com. My wife has a 04 Subaru Forester. The other night while changing the oil I noticed the external filter.
I asked the board if it was the same size as the oil filter. Someone came on and said (yes, don't touch it). Later that poster said that it was a "lifetime filter". Now, I know as well as you that the tranny oil doesn't see the same rigors as a motor oil filter. But to say this filter is to stay on for the life of the vehicle and not get changed (even after breakin) is assinine.
The poster said that tranny fluid is to go 45k to 60k before changing and to "never touch" the filter. What are your thoughts?
I'm in somewhat of a heated debate over at http://forums.nasioc.com. My wife has a 04 Subaru Forester. The other night while changing the oil I noticed the external filter.
I asked the board if it was the same size as the oil filter. Someone came on and said (yes, don't touch it). Later that poster said that it was a "lifetime filter". Now, I know as well as you that the tranny oil doesn't see the same rigors as a motor oil filter. But to say this filter is to stay on for the life of the vehicle and not get changed (even after breakin) is assinine.
The poster said that tranny fluid is to go 45k to 60k before changing and to "never touch" the filter. What are your thoughts?
I never change the fluid on my trannies, in fact, i go by the if you havnt changed it after 50k miles, then you should never change it. Never had a tranny failure before 230k miles, and i have a 5-speed with 419k miles, original fluid. 5-speeds never need changing. I dont care what any of you say, a 5-speed with a ATF fluid in it, never needs to be changed.
My Ford Explorer had a 5 speed with ATF. It started to grind at 100k. I put in new ATF and made it another 10k before having to change.
My experiences with an '87 Nissan 300ZX auto:
At around 90K (first bought the car) I dropped the pan and cleaned it and installed a new filter screen. There was a good bit of gray crud in the pan along with some brass...and the ATF was brownish red. Added about 3 quarts ATF.
A few K miles later I decided to do a complete flush using regular ATF thru the radiator cooling lines where I basically replaced about 6 quarts of around a 7 quart capacity. Got some sloppy shifting...no serious slipping though.
After about 2K miles I did this full flush again...
Thru this series of flushes, the old ATF was getting cleaner...with less suspended stuff (seemed to be very small particles and clumps of varnish?)...when comparing the old ATF with new in a clear bottle.
I then after 2K I repeated the full flush using 6 quarts Mobil 1 synth ATF.
After this last complete flush the trans shifted very solidly.
But in the fall when the weather got colder, I had a problem where the trans, when starting out, would fail to downshift into 1st at the first stop...but would suddenly clunk down into 1st when trying to get going from that stop. Sounded real bad.
After some research, I added a bottle of Lubegard trans additive to the trans and after doing this one more time...it hasn't happened since.
Now, 50K miles later, the trans is doing as well as it always has...shifting just fine with just a few anomalies now and then. And I have run the car rather hard.
I now do a complete 6 quart flush with Mobil synth ATF every 15K miles after cleaning the pan and then add the right amount of Lubegard.
So I went from a trans that I thought might be on it's last legs to one that has functioned just fine for the last 50 K miles.
My belief is that this type of slow flush (using the operation of the trans to do the flushing) is less risky that using chemicals or a machine.
Though Lubegard does now sell a flushing chemical.
At around 90K (first bought the car) I dropped the pan and cleaned it and installed a new filter screen. There was a good bit of gray crud in the pan along with some brass...and the ATF was brownish red. Added about 3 quarts ATF.
A few K miles later I decided to do a complete flush using regular ATF thru the radiator cooling lines where I basically replaced about 6 quarts of around a 7 quart capacity. Got some sloppy shifting...no serious slipping though.
After about 2K miles I did this full flush again...
Thru this series of flushes, the old ATF was getting cleaner...with less suspended stuff (seemed to be very small particles and clumps of varnish?)...when comparing the old ATF with new in a clear bottle.
I then after 2K I repeated the full flush using 6 quarts Mobil 1 synth ATF.
After this last complete flush the trans shifted very solidly.
But in the fall when the weather got colder, I had a problem where the trans, when starting out, would fail to downshift into 1st at the first stop...but would suddenly clunk down into 1st when trying to get going from that stop. Sounded real bad.
After some research, I added a bottle of Lubegard trans additive to the trans and after doing this one more time...it hasn't happened since.
Now, 50K miles later, the trans is doing as well as it always has...shifting just fine with just a few anomalies now and then. And I have run the car rather hard.
I now do a complete 6 quart flush with Mobil synth ATF every 15K miles after cleaning the pan and then add the right amount of Lubegard.
So I went from a trans that I thought might be on it's last legs to one that has functioned just fine for the last 50 K miles.
My belief is that this type of slow flush (using the operation of the trans to do the flushing) is less risky that using chemicals or a machine.
Though Lubegard does now sell a flushing chemical.
MolaKule
Staff member
My experience is that you should change the ATF (and any filters) within 10k for a new vehicle, and immediateley if you buy a used one, then change out within every 30k miles (dino) or 75k (Synthetic).
This way, you can detect abnormal fluid or shifting problems through analysis. If the car is bought used, then a fresh fluid change (pan fluid change or complete replacement via fresh fluid supply in lines) will uncover future problems.
I prefer the drain pan fluid change with AutoRX or LC at 7k intervals as this method slowly removes varnish and deposits from tight tolerance valves and valve bodies.
Most AuTo transmission fluids are never changed soon enough and this can result in varnishing of valves, valve bodies, hydraulic pistons, solenoids, etc, and clutch deposits coating internals.
When fresh fluid is installed in a AT that has not had regular fluid changes, the crud brakes loose because the dispersants and detergent adds in the fresh fluid are putting the old deposits into suspension which then get circulated throughout the tranny.
My view is that you either never change the fluid and let the transmission die with 50 weight tranny fluid, or you change as above and let it live.
Relatively speaking, fluids are very cheap compared to major overhauls.
This way, you can detect abnormal fluid or shifting problems through analysis. If the car is bought used, then a fresh fluid change (pan fluid change or complete replacement via fresh fluid supply in lines) will uncover future problems.
I prefer the drain pan fluid change with AutoRX or LC at 7k intervals as this method slowly removes varnish and deposits from tight tolerance valves and valve bodies.
Most AuTo transmission fluids are never changed soon enough and this can result in varnishing of valves, valve bodies, hydraulic pistons, solenoids, etc, and clutch deposits coating internals.
When fresh fluid is installed in a AT that has not had regular fluid changes, the crud brakes loose because the dispersants and detergent adds in the fresh fluid are putting the old deposits into suspension which then get circulated throughout the tranny.
My view is that you either never change the fluid and let the transmission die with 50 weight tranny fluid, or you change as above and let it live.
Relatively speaking, fluids are very cheap compared to major overhauls.
Do those Toyotas have a filter in the sump or just a screen?...I think it's a screen.
Ken [/QB][/QUOTE]
`
My Toyota only has the fine mesh screen. I just had the pan off to replace the gasket and found the screen so clean I didn't bother to take it out to clean it. I did add a magnet to the pan.
My Vibe is the same way, no filter just a mesh screen.
Flushing with synth every 15K might seem like overkill...but these trans are apparently difficult to rebuild and some trans people won't even try. $60 each 15K vs $1500-$2000 for a rebuild.
Another flush method with this trans is to braze a plug into the pan and change out 3 quarts of reg ATF at every engine oil change. One guy doing this said he was at 180K miles with his trans.
I just did a tranny flush + pan drop + filter change in my wifes 2000 Ford Taurus with a Ax4n tranny. These trannys can be problematic if not taken care of.
I was horified
to find out that the oem (supposed to be Merc V) was still in after 82K miles!! We had just purchased this vehicle about 10k mi. ago and was assured that all fluids were flushed. Yeah right, bleeping cheapskates!
I've never seen Atf be darker than used motor oil till now. I'm sure glad that I dropped the pan and filter and did a very thourgh flush with some new Valvoline Merc V fluid.
The tranny did not have any troubles, so I hope that I'm okay, but to be on the safe side I'll prolly do another flush and filter in about 15k to 20K.
I was horified
I've never seen Atf be darker than used motor oil till now. I'm sure glad that I dropped the pan and filter and did a very thourgh flush with some new Valvoline Merc V fluid.
The tranny did not have any troubles, so I hope that I'm okay, but to be on the safe side I'll prolly do another flush and filter in about 15k to 20K.
I've heard that a flush can dislodge particles that are better left alone, often resulting in transmission problems shortly after. To be safe, I always just change the fluid and filter with no flush.
02supercrew,
It is possible the tranny was flushed at 82,000 miles. Probably the first flush. If so, then the new atf cleaned out the tranny and that's why the fluid is so dark.
I always advise folks to re-flush in 2-3K miles if their first flush is after 75K miles. The new atf will get firty fairly quickly.
DEWFPO
It is possible the tranny was flushed at 82,000 miles. Probably the first flush. If so, then the new atf cleaned out the tranny and that's why the fluid is so dark.
I always advise folks to re-flush in 2-3K miles if their first flush is after 75K miles. The new atf will get firty fairly quickly.
DEWFPO
I should have made my self clearer, the car has 82k on it right now....I bought it 10K ago. The OEM filter was still in, and the fluid was so dark and burnt smelling, that there is no way that it could have been flushed in my opinion. Not to mention that the cheap line retainers were still on (most shops toss these).
Anyway, she's running good, and that's all that matters to me.
I changed the gear oil in my '94 tercel 4 speed with 76K miles to ST 80W90 and added a bit of AutoRx. I plan on changing out the ST for Mobil 1 after 1000 miles or so. Then Im going to drive the car into the ground with the mobil 1 in it. I havent noticed any problems. Should I expect any?
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