roegs

I've never really watched my trans temp guage too much, but happened to notice this am that it was warming up slightly faster than the engine coolant. How can this be? Certainly the tranmission sump could not be that warm after only a few miles of driving. I'm assuming the sensor is in the sump, but maybe I'm wrong. Anyone else noticed this?

TRMIN8TR

same here

OD52

Yep, things that make you go hmmmmm..........

manic5_2001

Correct me if I am wrong but I dont think out temp guages read true temps........... I think they are simple on and off switched guages. This meaning that they read cold untile you get into the operating temperature range then read normal, untile you get too hot then read hot, but not a 1 to 1 ratio of movment. So maybe the operating temp for the trans is lower than for the engine. So naturally it would read normal operating temp quicker than the engine. Once again if I am wrong let me know.

justice1736

iTrader: (1)

you also have to think that the transmission is smaller than the engine. hence less fluid to warm up and less plumbing that the coolant would have to run through to warm up. also fluid make up has a lot to contribute to how fast a fluid will heat up. so composition might factor in along with size. im no scientist but just doin a little guestamation.

icantdrive55

I agree about the tranny temp gauge. It's the same as the oil pressure gauge. These are essentially 'idiot lights' in gauge form--a digital-analog gauge that is either on/off. If the electrical signal from the sender is within the acceptable range, the gauge will read 'Normal'. If the oil pressure or the tranny temp gets out of the acceptable range, the gauge will 'turn on' and read low (oil) or hot (tranny).

I wish the Ford engineers would have added just a little to the bottom line cost of these long-lived trucks and optioned true analog gauges, which are useful for monitoring vehicle health and keeping track of age-related changes in the engine and tranny.

09fone50

Noticed the same thing this morning

KingRanchUT

Yep. Noticed the same thing this morning. I figured a small amount of oil under pressure in the clutch packs moving a heavy truck, might be the cause.

husker1818

i was going to post this but you beat me to it. notice it a few days ago when it did get cold but it slipped my mind. the f150 does great in cold/snow but it does not warm up quick. it take a long time to get warm.

I don't buy the idea that it is an idiot switch. How can it be an idiot switch when it moves gradually? When your cooling system overheats it will gradient temperature reading and for example when your thermo. goes out (stuck closed or open) it will act funny too.

Oil pressure gages immediately move once the engine is started. Tranny temp has only friction, where engine has combustion, friction, air movement, etc... It should naturally get warmer than tranny, in theory. But that does not seem to be the case. You would figure with a 5.4L V8, things should get pretty hot, pretty quick!

But...if you let your truck warm up before you drive off then this should never be an issue!!!!!!!

roegs

Thanks for the responses. This is my first Ford, so I'm learning new things all the time. Its hard for me to believe that the guage senders are stepped vs. linear, but I guess its possible.

My last truck was a GM Duramax with Allison transmission. It also had a transmission temp guage. In the dead of winter it takes quite a while to warm up the transmission. There is just not enough heat generated (unless you are towing) to warm up the fluid. Keep in mind that the transmission pan has a large surface area, and dissipates quite a bit of heat as the cold air passes over it.

As for the 5.4 being show to warm up, I agree. My guess is that its probably due to the aluminum heads. Aluminum is a great conductor of heat. The same thing occured on the Duramax diesel. Just be glad we have electric radiator fans to keep the underhood airflow down while it warms up! (Joke related to the electric fan thread)