Trans Temps

mohead1

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2008 F450, 4.88 gear, 4wd. Was running the interstate today, was doing approx. 75 mph, 2700 rpm, temp outside showed 92. My Livewire was showing 223 deg on trans temp but the factory gauge was to the left, good side of center. i have the alarm set at 220 deg so it was flashing red. Backed the truck down to 70 mph and the temp slowly went down to 216-219 deg. It has done this before, sudden temp issue, when its normally in the 178-185 range. I was unloaded, no trailer, traveling empty. My first thought was thermostat sticking in trans, but factory gauge was showing well to the good. Where does the PCM get the temp signal from? Possibly bad sensor? Or the signal was accurate and the factory gauge is crap? Fairly new trans, do not want to have issues. If i was pulling who knows how high it would have gone. Mark K. mentioned once on one of the forums, that the trans will live at 300 deg, but still, i see 220 and im very worried. Any insight?

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6.0 Tech

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Temp sensor is in the valve body. Don’t think that’s the issue, as with all the dash gauges they’re just stepper motors, and more or less idiot lights. Do you have the inline filter? If you do it will be bolted to the bottom 2 bell housing bolts, I’ve seen plugged filters cause temp issues. Typically it will bypass in the filter and not go thru the cooler. Other than that, the obvious airflow restriction check would be one thing I’d do.


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mohead1

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No, my version of 5r110 doesnt have the inline filter. I checked the hoses where it transitions from metal to rubber into the radiator then back out to the cooler and the return. All seems ok. Its done this twice now, and im concerned w damage to a newly built trans. I remember the little sensor up between the solenoids now, i had to change that once on the original trans when the gauges started going whacko. Will increased pump pressure cause this?

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Mark Kovalsky

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Get Forscan so that you can see what the temp sensor is reporting. The gauge will stay in the middle until the temp gets to around 260°F.

You can download Forscan free at www.forscan.org. Their webpage shows how to select an adapter to plug into the OBDII port. I bought mine from Amazon for less than $30.
 

mohead1

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Thanks Mark, I will work on that

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6.0 Tech

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Sorry it took so long. I don’t believe higher pump pressures will cause higher temps. I’ve got a fully built trans in my truck, and I like it to shift hard as hell. Got a temp sensor in the pressure port, and it typically reads around 170-180, occasionally see just over 200 depending on ambient and load behind the truck. Also depends on driving conditions, stip and go vs highway.


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mohead1

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Sorry it took so long. I don’t believe higher pump pressures will cause higher temps. I’ve got a fully built trans in my truck, and I like it to shift hard as hell. Got a temp sensor in the pressure port, and it typically reads around 170-180, occasionally see just over 200 depending on ambient and load behind the truck. Also depends on driving conditions, stip and go vs highway.


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You got a sender that fit into the pressure port? Tell me more. I tend to trust the Livewire but i never had issues w the previous trans, and the fluid is good and the filter has no trash. This trans was built for 600hp rating, im figuring w mods im making in the 400hp neighborhood. These sudden high temps unloaded worries me. If i reduced speed/rpm it goes back down.
If i had the gooseneck on and loaded it would be way high
 

6.0 Tech

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You got a sender that fit into the pressure port? Tell me more. I tend to trust the Livewire but i never had issues w the previous trans, and the fluid is good and the filter has no trash. This trans was built for 600hp rating, im figuring w mods im making in the 400hp neighborhood. These sudden high temps unloaded worries me. If i reduced speed/rpm it goes back down.
If i had the gooseneck on and loaded it would be way high


I’ll have to look this weekend if I’ve got an adaptor in it or not. It’s an autometer gauge with their sender


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mohead1

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Cool, let me know if you get a chance. Ive put a pressure gauge on there before on another 5r110 and its seems like it was some bastard metric adapter to get to the pressure hose fitting

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