Operating temperature of ATF
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I don't think "over-cooling" would be an issue. Why do you want to install a tranny cooler? Do you tow a lot? That is the only reason I can think of to install one aftermarket. And if you tow sometimes but not often, I would just fill it with a quality synthetic ATF and call it good.
Originally Posted By: takax2040
Is there an ideal operating temperature for AT fluids like how MTF works better when it's warmed up.
Cause I was wondering if I installed an ATF cooler will it 'overcool' the ATF and lead to poor shifting etc.
There is an ATF Cooler that will not overcool the fluid, its a stacked plate design, B&M is one of the manufactures that makes a trans cooler like this. It works on this principle, when the trans fluid is cool (thick) it bypasses the cooler, when the fluid is hot (thin) the trans fluid goes through the cooler. This type of trans cooler is great for the wintertime becuase if its really cold out then you know the trans fluid is bypassing the cooler and not getting overcooled.
The tube and fin type trans cooler always has trans fluid flowing through it so there is obviously a chance of the fluid getting overcooled. I remember seeing guys who had this type of cooler put a piece of cardboard over there tube and fin cooler in the wintertime. I would think if the trans fluid were cooled to much that this could lead to sluggish shifting.
Is there an ideal operating temperature for AT fluids like how MTF works better when it's warmed up.
Cause I was wondering if I installed an ATF cooler will it 'overcool' the ATF and lead to poor shifting etc.
There is an ATF Cooler that will not overcool the fluid, its a stacked plate design, B&M is one of the manufactures that makes a trans cooler like this. It works on this principle, when the trans fluid is cool (thick) it bypasses the cooler, when the fluid is hot (thin) the trans fluid goes through the cooler. This type of trans cooler is great for the wintertime becuase if its really cold out then you know the trans fluid is bypassing the cooler and not getting overcooled.
The tube and fin type trans cooler always has trans fluid flowing through it so there is obviously a chance of the fluid getting overcooled. I remember seeing guys who had this type of cooler put a piece of cardboard over there tube and fin cooler in the wintertime. I would think if the trans fluid were cooled to much that this could lead to sluggish shifting.
Over cooling is an issue in cooler climates, like Northern USA or Canadian winters.
Since you're in Malaysia, I'd wager that over-cooling shouldn't be an issue.
A good ATF range is 110°F-160°F.
Thermostats can be added to ATF coolers to prevent overcooling and to allow quicker warmups.
Since you're in Malaysia, I'd wager that over-cooling shouldn't be an issue.
A good ATF range is 110°F-160°F.
Thermostats can be added to ATF coolers to prevent overcooling and to allow quicker warmups.
110 to 160 is very well and good, but good luck getting only 160 with a warmed up car in mild weather conditions!
ATF problems are virtually always from overheating.
In Malaysia, I would get an aftermarket cooler, for sure.
And install it AFTER the stock cooler in the radiator [in series].
ATF problems are virtually always from overheating.
In Malaysia, I would get an aftermarket cooler, for sure.
And install it AFTER the stock cooler in the radiator [in series].
I'll risk throwing in my completely non-professional opinion on ATF temperature after two professionals have already responded above.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
Originally Posted By: BearZDefect
I'll risk throwing in my completely non-professional opinion on ATF temperature after two professionals have already responded above.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
I think 150-180 is a good range. Thats about where my car runs the best. Only time it goes higher than 180 is if Im pulling a hill with the TC unlocked. Highest I have ever seen is just over 200F pan temperature. Usually will drop right back to 188-190 once load drops and it locks up again. Have to remember though this is pan fluid temp so fluid temperature coming out of the trans to the cooler is probably much hotter depending on the state of lockup.
I'll risk throwing in my completely non-professional opinion on ATF temperature after two professionals have already responded above.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
I think 150-180 is a good range. Thats about where my car runs the best. Only time it goes higher than 180 is if Im pulling a hill with the TC unlocked. Highest I have ever seen is just over 200F pan temperature. Usually will drop right back to 188-190 once load drops and it locks up again. Have to remember though this is pan fluid temp so fluid temperature coming out of the trans to the cooler is probably much hotter depending on the state of lockup.
In stop and go driving my ATF temp goes as high as 160 degrees F and thats measuring from the transmission line going to the cooler (scanguage reading ATF temp probe.) It comes down as the TC locks when driving over 45mph.
I thought operating ATF temp is the same as the coolant temp?
I thought operating ATF temp is the same as the coolant temp?
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ATF does not run at coolant temperature, except by coincidence.
Trans fluid is routed to a heat exchanger in the radiator, then back to the trans.
This will warm cold fluid, and cool very hot fluid. The radiator is at a much lower temperature than the engine's thermostat.
ATF is thin when cold. The new types are even better about this.
I can't see any situation in normal street driving where it would be too thick and cause problems because it is cold/cool.
Trans fluid is routed to a heat exchanger in the radiator, then back to the trans.
This will warm cold fluid, and cool very hot fluid. The radiator is at a much lower temperature than the engine's thermostat.
ATF is thin when cold. The new types are even better about this.
I can't see any situation in normal street driving where it would be too thick and cause problems because it is cold/cool.
Originally Posted By: Onmo'Eegusee
Originally Posted By: BearZDefect
I'll risk throwing in my completely non-professional opinion on ATF temperature after two professionals have already responded above.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
I think 150-180 is a good range. Thats about where my car runs the best. Only time it goes higher than 180 is if Im pulling a hill with the TC unlocked. Highest I have ever seen is just over 200F pan temperature. Usually will drop right back to 188-190 once load drops and it locks up again. Have to remember though this is pan fluid temp so fluid temperature coming out of the trans to the cooler is probably much hotter depending on the state of lockup.
This seems to be the normal range for my truck. In the winter it will get up to about 150 when warm. It will get between 175-180 during normal driving in the summer, and as high as 190 with steep hills and/or towing. IIRC, 191*F is the highest I have ever seen it read on the Scangauge. The fluid has never looked or smelled burnt.
Originally Posted By: BearZDefect
I'll risk throwing in my completely non-professional opinion on ATF temperature after two professionals have already responded above.
From what I've read, and ideal ATF operating temperature range is about 150-180 F.
A thermostat in the ATF cooling loop is surely a great help in cold weather when you take mostly short trips. Like engine oil, if your vehicle doesn't come with an OEM ATF thermostat, the ATF barely warms up to an acceptable temperature before shutdown.
I think 150-180 is a good range. Thats about where my car runs the best. Only time it goes higher than 180 is if Im pulling a hill with the TC unlocked. Highest I have ever seen is just over 200F pan temperature. Usually will drop right back to 188-190 once load drops and it locks up again. Have to remember though this is pan fluid temp so fluid temperature coming out of the trans to the cooler is probably much hotter depending on the state of lockup.
This seems to be the normal range for my truck. In the winter it will get up to about 150 when warm. It will get between 175-180 during normal driving in the summer, and as high as 190 with steep hills and/or towing. IIRC, 191*F is the highest I have ever seen it read on the Scangauge. The fluid has never looked or smelled burnt.
Originally Posted By: mechtech2
ATF does not run at coolant temperature, except by coincidence.
Trans fluid is routed to a heat exchanger in the radiator, then back to the trans.
This will warm cold fluid, and cool very hot fluid. The radiator is at a much lower temperature than the engine's thermostat.
ATF is thin when cold. The new types are even better about this.
I can't see any situation in normal street driving where it would be too thick and cause problems because it is cold/cool.
Mine does not not go through the radiator.
ATF does not run at coolant temperature, except by coincidence.
Trans fluid is routed to a heat exchanger in the radiator, then back to the trans.
This will warm cold fluid, and cool very hot fluid. The radiator is at a much lower temperature than the engine's thermostat.
ATF is thin when cold. The new types are even better about this.
I can't see any situation in normal street driving where it would be too thick and cause problems because it is cold/cool.
Mine does not not go through the radiator.
190 when towing up a hill is outstanding!
Be happy!
Be happy!
Interesting. If it does not go through the radiator then where does it go? Can't recall an automatic from the factory that did not have a trans cooler in the radiator.
Mine has two, and a thermostat to boot. Typical temp is 150-180, and it gets close to 200 on track days. You want it to get hot, but if you're using a good fluid the modern auto is 'cool' with that!
And thin fluids, has anyone seen any Dexron VI? That stuff is like water!
Mine has two, and a thermostat to boot. Typical temp is 150-180, and it gets close to 200 on track days. You want it to get hot, but if you're using a good fluid the modern auto is 'cool' with that!
And thin fluids, has anyone seen any Dexron VI? That stuff is like water!
On my Marauder I noticed that after I flushed out the Motorcraft Mercon V and went to Amsoil ATF that my pan temps dropped by about 30 degrees.
I think this is because the Motorcraft Mercon V is a semi synthetic fluid and the Amsoil ATF is a full synthetic fluid.
If you are using a stacked plate design trans cooler like the one B&M makes then you do not need a thermostat before the cooler since the B&M unit has a bypass built into it that only lets the fluid travel through the cooler when it gets hot ( thin ). When the fluid is cool ( Thick ) it bypasses the cooler.
I think this is because the Motorcraft Mercon V is a semi synthetic fluid and the Amsoil ATF is a full synthetic fluid.
If you are using a stacked plate design trans cooler like the one B&M makes then you do not need a thermostat before the cooler since the B&M unit has a bypass built into it that only lets the fluid travel through the cooler when it gets hot ( thin ). When the fluid is cool ( Thick ) it bypasses the cooler.
I answered a direct question about coolant temp and ATF temp.
But, newer Crown Vics have an ATF to air cooler.
This is rare and unusual.
But, newer Crown Vics have an ATF to air cooler.
This is rare and unusual.
The predominant American design would be to have an ATF type of tube reservoir that goes into one of the end tanks in the radiator. I am not sure if it is to bring it up to temperature quicker or for cooling. I do know overly cool ATF doesn't allow the torque converter to lock up and on some it won't go into overdrive until it reaches operating temp. I tow a 5000lbs trailer every couple of weeks (O/D off), and have 305,000kms+ on odo.
My suburban has both, in-rad, and I have a radiator type factory installed 10in cooler in front of the rad. I have also installed a in-line spin-on filter just below the fan shroud which 'sees' a lot of air movement off the fan. I do a drain/refill 4L+ every year and the trans still shifts like new, & the ATF still looks bright red and smells new. ATF is cheap, and the infusion of new fluid is key to its longevity as heat is the #1 killer to auto transmissions. If the auto trans has basic cooling setup IMO dex3/dex6 dino with 1/4 to 2/3 sump changeout every year will provide better longevity than full synthetic once every few years...and cheaper too.
My suburban has both, in-rad, and I have a radiator type factory installed 10in cooler in front of the rad. I have also installed a in-line spin-on filter just below the fan shroud which 'sees' a lot of air movement off the fan. I do a drain/refill 4L+ every year and the trans still shifts like new, & the ATF still looks bright red and smells new. ATF is cheap, and the infusion of new fluid is key to its longevity as heat is the #1 killer to auto transmissions. If the auto trans has basic cooling setup IMO dex3/dex6 dino with 1/4 to 2/3 sump changeout every year will provide better longevity than full synthetic once every few years...and cheaper too.
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Originally Posted By: mechtech2
I answered a direct question about coolant temp and ATF temp.
But, newer Crown Vics have an ATF to air cooler.
This is rare and unusual.
I managed to skip over the question. Didnt see it, whoops.
But, Yup.
Has a pretty decent size OTA cooler, with thermostat.
I answered a direct question about coolant temp and ATF temp.
But, newer Crown Vics have an ATF to air cooler.
This is rare and unusual.
I managed to skip over the question. Didnt see it, whoops.
But, Yup.
Last edited by a moderator:
Originally Posted By: SteveSRT8
Interesting. If it does not go through the radiator then where does it go? Can't recall an automatic from the factory that did not have a trans cooler in the radiator.
Mine has two, and a thermostat to boot. Typical temp is 150-180, and it gets close to 200 on track days. You want it to get hot, but if you're using a good fluid the modern auto is 'cool' with that!
And thin fluids, has anyone seen any Dexron VI? That stuff is like water!
My truck has a separate cooler with a thermostat. The power steering cooler uses the radiator where the AT lines would go. On the other hand, my Explorer cooled the ATF with the rad and used a small separate cooler for the power steering.
Interesting. If it does not go through the radiator then where does it go? Can't recall an automatic from the factory that did not have a trans cooler in the radiator.
Mine has two, and a thermostat to boot. Typical temp is 150-180, and it gets close to 200 on track days. You want it to get hot, but if you're using a good fluid the modern auto is 'cool' with that!
And thin fluids, has anyone seen any Dexron VI? That stuff is like water!
My truck has a separate cooler with a thermostat. The power steering cooler uses the radiator where the AT lines would go. On the other hand, my Explorer cooled the ATF with the rad and used a small separate cooler for the power steering.
Most hard core 4X4 types like me get rid of the factory water based OEM coolers because they fail regularly and they are not that effectice. Some are just one tube running through the end cap of the rad and some are 2-3 stacked plates either way they arenot that great. Automatics do not like water of any kind in fact water will ruin the material on the friction plates.
Many like to run air only coolers and either mouth them under the grill in fron of the rad or in the frame some place with an electric pan to keep air moving over it.
That is one thing I never liked about GM ax cooler for the Suburban and other vechiles. It still passed the atf through the rad atf cooler then into the air cooler inn front of the grill then back to the trans.
Many like to run air only coolers and either mouth them under the grill in fron of the rad or in the frame some place with an electric pan to keep air moving over it.
That is one thing I never liked about GM ax cooler for the Suburban and other vechiles. It still passed the atf through the rad atf cooler then into the air cooler inn front of the grill then back to the trans.
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I do know overly cool ATF doesn't allow the torque converter to lock up and on some it won't go into overdrive until it reaches operating temp.
I've only note this from truck owners ..usually heavier duty. Otherwise I've seen engine coolant temp used as a trigger for converter lockup. Now in some systems it may use the higher heat production of the open converter to thin the fluid to bring it more into range where the fancy 'tronics can continue to provide those "velvety smooth shifts" (that consumers protested about in front of the big 3's home offices demanding them) over broader temp spans ..but that would be my speculation.
My numb 30RH requires 160F from the engine coolant temp sensor for the PCM to enable the ground for the converter clutch.
I do know overly cool ATF doesn't allow the torque converter to lock up and on some it won't go into overdrive until it reaches operating temp.
I've only note this from truck owners ..usually heavier duty. Otherwise I've seen engine coolant temp used as a trigger for converter lockup. Now in some systems it may use the higher heat production of the open converter to thin the fluid to bring it more into range where the fancy 'tronics can continue to provide those "velvety smooth shifts" (that consumers protested about in front of the big 3's home offices demanding them) over broader temp spans ..but that would be my speculation.
My numb 30RH requires 160F from the engine coolant temp sensor for the PCM to enable the ground for the converter clutch.
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