Change automatic transmission fluid?

Interesting explanation. By this line of reasoning, it would be beneficial to change the fluid often early in the transmissions life but, at some unknown point, stop changing the fluid so the old fluid can extend the life of the nearly worn out transmission.

The theory is a scheduled transmission service helps minimize transmission wear depending on the lifespan of the actual fluid's integrity. Wear will always occur so the goal is to minimize that wear by changing the fluid. Something like an every 40k schedule. You don't have to stop and should be able to extend it to like 200k miles+ because the amount of protection provided by periodic fluid changes allows for less wear as compared to 100k miles with no fluid change at all which at that point is a crap shoot depending on the existing wear. If the wear isn't too bad then the 100k initial fluid change is good....but if there was significant wear then don't be surprised if the transmission fails shortly thereafter. I think a good (and serviced) transmission should last into 200k miles. We here folks all the time with 200k miles on original non-serviced transmissions. But then what type of transmission is it? Is it a real simple design? The Skyactiv transmission from what I read is complex and has multi-plates that act like a dual clutch transmission . More complex transmissions from what I read require servicing.
 
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This:
I think this happens more often than it should-----> Wrong AT fluid is used during the service
plus these:
1. The non-serviced high mileage transmission oil may develop crud.
2. The non-serviced high mileage transmission oil is thicker and laden with wear particles (shavings).
3. The transmission parts have deteriorated and actually rely on said crud and metal shaving laden oil to fill voids and to operate.
4. Changing the metal shaving laden fluid and removing crud allows the transmission to operate as it should WITH wear. No matter what that wear is present.
5. The transmission now with new fluid will simply act like a transmission with wear would. Depending on the level of wear, the transmission will either operate poorly or possibly fail despite having new fluid.
should be the proper guidelines for automatic transmission fluid change. But calling "transmission oil" is something I don't get used to... ;)

BTW, I was totally surprised to find out the 5-speed Steptronic automatic transmission in our 2000 BMW 528i was actually made by GM.

The other funny thing I'd found out was VW's OEM automatic transmission fluid has 2 years of shelf life stamped on the bottle. In the mean time they claimed their auto tranny has life-time fluid and fluid change is not needed!
 
This:
plus these:
should be the proper guidelines for automatic transmission fluid change. But calling "transmission oil" is something I don't get used to... ;)

BTW, I was totally surprised to find out the 5-speed Steptronic automatic transmission in our 2000 BMW 528i was actually made by GM.

The other funny thing I'd found out was VW's OEM automatic transmission fluid has 2 years of shelf life stamped on the bottle. In the mean time they claimed their auto tranny has life-time fluid and fluid change is not needed!

Yeah BMW at that time used 2 or 3 different transmission suppliers. GM and I think ZF. Can't recall the third.

VW had a recall on their DSG transmission a few years ago. They offered 100k warranties on repaired ones with the condition that owners have transmission fluids changed every 40k miles otherwise warranty won't be honored. This is not your typical DIY job nor cheap. $400-$500 at dealer, about $250 in DIY parts/tools. Mazda's transmission fluid drain/fill or heck even flush is much much cheaper. A drain/fill is an easier DIY job.
 
Mazda's transmission fluid drain/fill or heck even flush is much much cheaper. A drain/fill is an easier DIY job.
I thought Mazda OEM ATF is pretty expensive too?
 
Doesn't make sense how metal shavings is good for the transmission on those BMWs . I'm thinking something else is a culprit of changing the oil at high mileage causing the transmission to fail .

Hypothesis :
Maybe as time and repeated heat cycles and changing weather and wear particles the oil viscosity gets thicker ? As mileage gets higher with the oil, the gears begin to wear more then they should and the tolerance is not as tight as it was , requiring thicker oil . And when people put in the "correct" oil viscosity , at that high mileage the required viscosity is too thin for it now .

But when changing the oil early consistently , the gears don't wear as fast or as much . So the recommended oil viscosity is sufficient for the still "tight" gear tolerances .


Oil over time, changing weather cycles, normal friction heat cycles, water condensation mixing etc... loses it's properties to lubricate and protect etc... Gear Oil does not get better over time and usage.

What you guys think ?
 
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I think around $15/quart and a drain/fill is around 5-6 quarts.

$15 a quart, and 12 quarts. This is what the Mazda dealership quoted me. $312, IIRC. I'm going to have it done here in a few weeks because it's still under warranty, and "why not?" If it doesn't kill it, it will help it. If it kills it, I get a new one for free, soo....
 
Doesn't make sense how metal shavings is good for the transmission on those BMWs . I'm thinking something else is a culprit of changing the oil at high mileage causing the transmission to fail .

Hypothesis :
Maybe as time and repeated heat cycles and changing weather and wear particles the oil viscosity gets thicker ? As mileage gets higher with the oil, the gears begin to wear more then they should and the tolerance is not as tight as it was , requiring thicker oil . And when people put in the "correct" oil viscosity , at that high mileage the required viscosity is too thin for it now .

But when changing the oil early consistently , the gears don't wear as fast or as much . So the recommended oil viscosity is sufficient for the still "tight" gear tolerances .


Oil over time, changing weather cycles, normal friction heat cycles, water condensation mixing etc... loses it's properties to lubricate and protect etc... Gear Oil does not get better over time and usage.

What you guys think ?
The cause doesn't much matter, IMO. The results do. The results are a dead tranny, and I don't mean Jenner.

However, I do think it's more about friction coefficients and clutch bands and fluid viscosity and detergents and valve-body passages and sludge...
 
$15 a quart, and 12 quarts. This is what the Mazda dealership quoted me. $312, IIRC. I'm going to have it done here in a few weeks because it's still under warranty, and "why not?" If it doesn't kill it, it will help it. If it kills it, I get a new one for free, soo....

If one was doing a flush but not for a drain/refill. IIRC Chris mentioned only about 5-6 quarts comes out on a drain.
 
If one was doing a flush but not for a drain/refill. IIRC Chris mentioned only about 5-6 quarts comes out on a drain.

The dealership that is doing it has a machine by BG (*?) and they remove the trans lines, hook it up, and it pulls out 12 quarts, and puts in 12 quarts. Whether the 12 it pulls out is 6 of the new it put in, I have no idea. That just is what it is.
 
The dealership that is doing it has a machine by BG (*?) and they remove the trans lines, hook it up, and it pulls out 12 quarts, and puts in 12 quarts. Whether the 12 it pulls out is 6 of the new it put in, I have no idea. That just is what it is.

Oh ok... I was just referencing home DIY method
 
Doesn't make sense how metal shavings is good for the transmission on those BMWs . I'm thinking something else is a culprit of changing the oil at high mileage causing the transmission to fail .

Hypothesis :
Maybe as time and repeated heat cycles and changing weather and wear particles the oil viscosity gets thicker ? As mileage gets higher with the oil, the gears begin to wear more then they should and the tolerance is not as tight as it was , requiring thicker oil . And when people put in the "correct" oil viscosity , at that high mileage the required viscosity is too thin for it now .

But when changing the oil early consistently , the gears don't wear as fast or as much . So the recommended oil viscosity is sufficient for the still "tight" gear tolerances .


Oil over time, changing weather cycles, normal friction heat cycles, water condensation mixing etc... loses it's properties to lubricate and protect etc... Gear Oil does not get better over time and usage.

What you guys think ?

Metal shavings are not good for ANY transmission lol. Make sure not to miss the point. The point of the matter at least for BMW transmissions was to take the lessor of two evils. A high mileage BMW with no transmission servicing ever done (thick fluid and metal shavings and all) is the lessor evil to a high mileage BMW that will (just now) have transmission fluids changed. The solution therefore are earlier scheduled changes as to prevent extensive metal shavings in the first place.



$15 a quart, and 12 quarts. This is what the Mazda dealership quoted me. $312, IIRC. I'm going to have it done here in a few weeks because it's still under warranty, and "why not?" If it doesn't kill it, it will help it. If it kills it, I get a new one for free, soo....

Someone wrote to Mazda corporate about transmission fluid servicing because it is not covered in the manual. The response back was to refer to a local dealership to have them assess and to follow their recommendations. My go to dealership recommends changing it at around 40k miles.


The dealership that is doing it has a machine by BG (*?) and they remove the trans lines, hook it up, and it pulls out 12 quarts, and puts in 12 quarts. Whether the 12 it pulls out is 6 of the new it put in, I have no idea. That just is what it is.

That's interesting. I actually did a flush/fill through our dealership. Came to $199 after coupon. My cousin went a different route with his used mazda3. He drain/filled the fluid. Ended up spending about half of what I paid.
 
The BG thing you're referring to is FLUSH, not drain and fill. You can do a poor man's flush also but changing the fluid and then removing the return line from the torque converter, starting the car and let the fluid drain out from the converter. In this process one needs to have careful measure of how much goes out and how much to put in. This process is definitely GENTLIER than the BG Flush method. Most of the metal shavings remain in the car, especially the tranny pan.
In my other cars, every 3rd. flush like above I drop the tranny pan, clean it out, put on a new gasket and re-seal it.
 
I think if you stay on top of the fluid services, a full fluid exchange is not required. That is just my .02 cents
 
Doesn't make sense how metal shavings is good for the transmission on those BMWs . I'm thinking something else is a culprit of changing the oil at high mileage causing the transmission to fail .

Hypothesis :
Maybe as time and repeated heat cycles and changing weather and wear particles the oil viscosity gets thicker ? As mileage gets higher with the oil, the gears begin to wear more then they should and the tolerance is not as tight as it was , requiring thicker oil . And when people put in the "correct" oil viscosity , at that high mileage the required viscosity is too thin for it now .

But when changing the oil early consistently , the gears don't wear as fast or as much . So the recommended oil viscosity is sufficient for the still "tight" gear tolerances .


Oil over time, changing weather cycles, normal friction heat cycles, water condensation mixing etc... loses it's properties to lubricate and protect etc... Gear Oil does not get better over time and usage.

What you guys think ?

I don't think it's the gears/bearings wearing out that cause the majority of automatic transmission failures.
Usually a solenoid starts acting funny and is slow to apply/release the fluid pressure from one of the many "clutches" within the transmission causing accelerated wear. Once one of the clutches is slipping it's only a matter of time before you loose a gear or 3.

The other problem might be something blocking one of the fluid passages also leading to insufficient fluid pressure and clutch slippage.
 
When I changed transmission fluid in my Tahoe, I used quick-connect fitting that goes into the fluid cooler (part of radiator). It is very easy to take the cooler line out, plug the fitting in, put the clear hose from the fitting into a bucket, start the engine. Wait until 1gal pumps out, then stop and add fresh fluid. Carry on until all the old fluid is replaced by the fresh one.
I also dropped the pan to replace a filter.
Now, CX-5 doesn't have a transmission filter, does it? So with the above method it is not very necessary to drop the pan, maybe to clean the magnet.
I'd prefer to do it this way when time comes to CX-5, no mess, very easy, all the fluid gets exchanged, and no flush involved from who knows what "machine"...
I wonder if the transmission cooler lines are as easy to disconnect from the radiator? Too cold to go take a look myself, does anyone know?
 
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