ATF Lacks Cleaning Detergents

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donjetman

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In case you don't know? atf has almost NO cleaning detergents. And why should it? There are no combustion gases and/or by products in a tranny. Engine oil has a lot of cleaning detergents in it.
ATF viscosity is thin, about like a 10-15 wt oil.
 

intheburbs

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Yup.

This is "straight from the horse's mouth"....

ACDelco DEXRON-VI ATF is a high performance, synthetic blend formulation that meets or exceeds the
stringent requirements of GM's DEXRON-VI specification and provides warranty protection for current
GM vehicles. It also provides improved performance in older GM vehicles, wherever DEXRON is
specified.
ADVANTAGES:
Outstanding friction performance and stability
Enhanced frictional properties
Improved anti-wear protection which contributes to
Higher oxidation stability, thus higher ageing stability
“Fill-for-life" oil. e.g. developed for maximum drain intervals

Nothing about cleaning/detergents
 

Dustin Jackson

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What are people doing with transmission fluid other than putting it in the transmission?
 

B-train

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Interesting info. I've used it for years for many different things and it's always seemed to help improve fuel systems (early 90's cars fuel injectors that didn't like ethanol fuel, and for washing motors for sticky lifters, etc). I wonder if the older dextron fluids were a different makeup? Maybe the different blend of additives seems to be beneficial outside of a transmission?
 

MWD_CTSV

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Dexron-VI is such a tough spec to meet, I think it can only be met with high grade PAO synthetic oil in high quantity. So that typically requires less additive to compensate for thermal decay and oxidation.

The additive package for ATF is quite a complex beast. The actual additives generally referred to as dispersants can have multiple properties such as friction control, antiwear, leakage control, aging control and cleanliness. Some additives can have positives in a small quantity, but negative in higher quantity, or interact with other additives in a negative or positive way.

Technically the dispersants have a detergent effect, and some refer to them as both, while the purists would say they are just dispersants. In some cases, the dispersants in ATF seem to be able to collect sludge and hold it in suspension at least visibly due to the color change in the fluid.
 

MWD_CTSV

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Also I think some of the same dispersants for ATF are also used as 'detergents' for fuel additives.

Specific to percentages, the additive licensed for making Dexron-VI (Afton Hitec 3491LV) is recommend as a 10% blend, whereas their additive for Dexron-III is something more like 18%. That probably has a lot to do with compensating for the lower quality base oils in the older spec fluid, but it would certainly mean more dispersants. To a degree that should mean better cleaning I would guess.

FWIW, the SDS for Berryman oil flush says it includes 2-5% polybutenyl succinimide, which is the same ashless dispersant used in the best ATF additive packages.
 

Marky Dissod

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What are people doing with transmission fluid, other than putting it in the transmission?
Don't some people put ATF in the engine crankcase to 'flush' it clean?
Never said that makes sense, just sayin' that I've heard that some people do it.
 

intheburbs

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I'm not sure about the GMT900 body style, but I remember reading that the GMT800 3/4 ton body style Yukon XL's and the Suburbans had the Allison Transmission as an available option IF you got the 8.1 big block engine. It wasn't available with the 6.0 engine though.

Don't some people put ATF in the engine crankcase to 'flush' it clean?
Never said that makes sense, just sayin' that I've heard that some people do it.

Yeah, not sure if that's an internet myth, or there was actually something to it 20 or 30 years ago. I'd heard that too - just before an oil change, pour in a quart of ATF and drive a few dozen miles to "clean" the engine internals.

That said, I do usually run half a can of Seafoam in the crankcase for a few miles right before an oil change.
 

B-train

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Yeah, not sure if that's an internet myth, or there was actually something to it 20 or 30 years ago. I'd heard that too - just before an oil change, pour in a quart of ATF and drive a few dozen miles to "clean" the engine internals.

That said, I do usually run half a can of Seafoam in the crankcase for a few miles right before an oil change.
As stated by @MWD_CTSV , I would say that older versions of the Dextron would have a better cleaning affect. I've used it with good results over the last 25 years for sticky fuel injectors, lifters that were noisy, etc. Interesting though, that the newer stuff has less of the dispersants (detergents) than the older versions. That may explain why it seemed more effective back in the day.

It does work, I still use some every few oil changes on both of my newer vehicles. You can physically see the oil color change in a short period as its cleaning out carbon/varnish from different areas or pieces of the engine internals. The oil always seems to stay cleaner longer after one of these changes.

Again, not a chemist, just someone who has seen the effects of using ATF in a different application over the years.
 

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