I am wondering if folks in colder climates would benefit from an ATF resembling engine oil (i.e. 5W-20)? I know that MTF is usually XW-XX, so why isn't ATF the same way?
Why isn't ATF like motor oil (i.e. 5W-20)?
- Thread starter Lyondellic
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I was wondering the same thing myself. I am pretty sure that transmissions in Canada don't last nearly as long as transmissions in warmer parts of the States.
ATF has a whole bunch of additives to it and high temperatures are a bigger concern than low temperatures, I would think. The low temperature issues are mostly parasitic drag and pumpability issues but there is always flow barring disaster.
ATF is generally a 10W or 0W20-ish thickness oil, from what I have seen.
ATF is generally a 10W or 0W20-ish thickness oil, from what I have seen.
Originally Posted By: Lyondellic
I am wondering if folks in colder climates would benefit from an ATF resembling engine oil (i.e. 5W-20)? I know that MTF is usually XW-XX, so why isn't ATF the same way?
I don't exactly follow - do you mean why isn't ATF labeled like motor oil, or why doesn't ATF behave like motor oil?
I can assure of why it not labeled 0W or 5W-10 or 20: So people don't put it in their engines. And yes ATF has "multiweight" viscosity.
I am wondering if folks in colder climates would benefit from an ATF resembling engine oil (i.e. 5W-20)? I know that MTF is usually XW-XX, so why isn't ATF the same way?
I don't exactly follow - do you mean why isn't ATF labeled like motor oil, or why doesn't ATF behave like motor oil?
I can assure of why it not labeled 0W or 5W-10 or 20: So people don't put it in their engines. And yes ATF has "multiweight" viscosity.
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Well, I say it's because it's a "one size fits all" type fluid. You don't change it seasonally ..or in any frequency that could be called routine.
That is, what would you do in the summer??
That is, what would you do in the summer??
Originally Posted By: Pablo
Originally Posted By: Lyondellic
I am wondering if folks in colder climates would benefit from an ATF resembling engine oil (i.e. 5W-20)? I know that MTF is usually XW-XX, so why isn't ATF the same way?
I don't exactly follow - do you mean why isn't ATF labeled like motor oil, or why doesn't ATF behave like motor oil?
I can assure of why it not labeled 0W or 5W-10 or 20: So people don't put it in their engines. And yes ATF has "multiweight" viscosity.
I think you may have answered my question. Based on the label information, one could easily assume that ATF is a straight weight fluid. Most engine oils, however, contain additives that help them flow at low temperatures, hence the XW-XX numbering.
According to your post, ATF is a multi-grade fluid it is just not marked as such. If this is correct, then you have answered my question.
Originally Posted By: Lyondellic
I am wondering if folks in colder climates would benefit from an ATF resembling engine oil (i.e. 5W-20)? I know that MTF is usually XW-XX, so why isn't ATF the same way?
I don't exactly follow - do you mean why isn't ATF labeled like motor oil, or why doesn't ATF behave like motor oil?
I can assure of why it not labeled 0W or 5W-10 or 20: So people don't put it in their engines. And yes ATF has "multiweight" viscosity.
I think you may have answered my question. Based on the label information, one could easily assume that ATF is a straight weight fluid. Most engine oils, however, contain additives that help them flow at low temperatures, hence the XW-XX numbering.
According to your post, ATF is a multi-grade fluid it is just not marked as such. If this is correct, then you have answered my question.
The reason that it doesn't have the viscosity listed is that its specification takes care of that detail. What I mean is there isn't different viscosity grades of mercon V offered from the same manufacturer, the spec took care of that info.
oil doesn't have the same convention as a standard. there isn't really a "mercon" motor oil, "dexron" oil. it is much more generic so it gets its viscosity listed.
oil doesn't have the same convention as a standard. there isn't really a "mercon" motor oil, "dexron" oil. it is much more generic so it gets its viscosity listed.
Originally Posted By: Lyondellic
I think you may have answered my question. Based on the label information, one could easily assume that ATF is a straight weight fluid. Most engine oils, however, contain additives that help them flow at low temperatures, hence the XW-XX numbering.
According to your post, ATF is a multi-grade fluid it is just not marked as such. If this is correct, then you have answered my question.
To expand a bit - indeed some ATF's do contain viscosity index enhancers and pour point agents. Most synthetic ATF's do not and can meet the low and high temperature requirements (and film strength) with the base oil mix alone.
I think you may have answered my question. Based on the label information, one could easily assume that ATF is a straight weight fluid. Most engine oils, however, contain additives that help them flow at low temperatures, hence the XW-XX numbering.
According to your post, ATF is a multi-grade fluid it is just not marked as such. If this is correct, then you have answered my question.
To expand a bit - indeed some ATF's do contain viscosity index enhancers and pour point agents. Most synthetic ATF's do not and can meet the low and high temperature requirements (and film strength) with the base oil mix alone.
Maybe it's already about as thin as it gets, oil wise.
Transmissions are spec'd for a certain type of ATF, and that takes care of the viscosity requirements automatically.
Transmissions are spec'd for a certain type of ATF, and that takes care of the viscosity requirements automatically.
Tom Sick's answer is the best. ATFs are not graded in the same way that most other lubricants are because individual OEM requirements are specified in much more detail, and they differ. If you look, for instance at low temperature requirements you will find different limits for -40C Brookfield in say the ZF spec compared to the GM spec. The same goes for KV 100C, across the various OEM specs you will find a variation in maximum or minimum values. The reason is that the ATF application is more complicated than most other automotive lubricant applications and therefore the specifications need to be more tightly defined to meet individual OEM requirements.
MolaKule
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Another reason is that ATF is a very specific hydraulic fluid and like most hydraulic oils, it transmits power, lubricates, and cools gearing. ATF does not see combustion gasses.
Motor oil does not transmit any siginifant power and does see combustion gasses.
Except for the new Dexron VI, most ATF's were speced for a 100 C viscosity of 7.5 cSt. Theorectically, an AT engineer would like to have a fluid with 0 viscosity, but one needs an oil film with a fluid of finite viscosity in order to lubricate the gear teeth.
The higher the viscosity index of the base fluids used for ATF, the better the low and high temp performance.
Motor oil does not transmit any siginifant power and does see combustion gasses.
Except for the new Dexron VI, most ATF's were speced for a 100 C viscosity of 7.5 cSt. Theorectically, an AT engineer would like to have a fluid with 0 viscosity, but one needs an oil film with a fluid of finite viscosity in order to lubricate the gear teeth.
The higher the viscosity index of the base fluids used for ATF, the better the low and high temp performance.
MolaKule
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