transmission overcooling?
Hotshot
Joined: Apr 2013
Posts: 10,121
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From: NH
Old oil doesn't lubricate as well as new oil. It increases frictional resistance between wear components, which will, of course, decrease fuel economy. Especially oil which has a few regen cycles on it and may have some diesel fuel contamination.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,725
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From: SE Florida
Higher temperatures lead to higher efficiency. Materials, including ATF, are MUCH more heat resistant now than they were not so long ago.
Post Fiend
Joined: Jan 2009
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From: Greenwood, SC
On my 2015 truck towing a trailer on the interstate my engine oil heats very quickly and stays between 208° and 212° all day until I have a hill that lasts more than a mile, then the oil can rise up to 224° kind of easily but returns to 212° quickly.
The transmission temp takes longer to come up to 195° and will fluctuate from 195° to 205° all day and it almost seems random. Uphill climbs and downhill engine braking both create friction I suppose so it jumps around constantly.
That's all I got....
The transmission temp takes longer to come up to 195° and will fluctuate from 195° to 205° all day and it almost seems random. Uphill climbs and downhill engine braking both create friction I suppose so it jumps around constantly.
That's all I got....
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Senior User
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My trans also takes a while to get up to temp. My oil, coolant, and trans all run about 195ish under normal driving with some minor fluctuation going up long hills and such.
Since these trucks don't run the trans cooler trough the main coolant system to help get and keep them up to temp, I would be concerned about condensation buildup on one that is constantly under temp.
Since these trucks don't run the trans cooler trough the main coolant system to help get and keep them up to temp, I would be concerned about condensation buildup on one that is constantly under temp.
Super Moderator
Joined: Aug 2003
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From: Isanti, MN
That's a persistent myth that just won't die. In-tank coolers never warm transmission fluid. Wouldn't matter anyway, since just about every Ford transmission put into Super Duties in the last ten years has a thermostat that severely restricts cooler flow until the transmission warms up.
Senior User
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That's a persistent myth that just won't die. In-tank coolers never warm transmission fluid. Wouldn't matter anyway, since just about every Ford transmission put into Super Duties in the last ten years has a thermostat that severely restricts cooler flow until the transmission warms up.
Either way, wouldn't condensation still be a concern if the trans wasn't getting up to temp?
Super Moderator
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From: Isanti, MN
https://www.ford-trucks.com/forums/1...l#post15722425
Either way, wouldn't condensation still be a concern if the trans wasn't getting up to temp?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,725
Likes: 2,651
From: SE Florida
It would if the coolant was warmer than the ATF, but it isn't. Sometimes in very hot ambients it can get close, but in cold weather the coolant near the trans cooler in the radiator is ALWAYS colder than the ATF. See the link Tom posted just above this post.
Senior User
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Yeah...well what do you know? [/sarcasm]
Thanks for setting me straight. I guess it is too late to do a Mythbusters episode since this is their last season.
Do you think this is some sort of new concern only because everybody now has a gauge and can monitor it whereas before transmissions may have been doing the same thing but nobody was really monitoring it?
Thanks for setting me straight. I guess it is too late to do a Mythbusters episode since this is their last season.
Do you think this is some sort of new concern only because everybody now has a gauge and can monitor it whereas before transmissions may have been doing the same thing but nobody was really monitoring it?