technokami

My 2006 4.6 has been sitting for the last few months while I have been working in the middle east. After replacing an alternator that seized while I was away, everything seemed to be working well. Driving today I received a high transmission fluid temp alert at 190*. The temp reading reached 206* before I reached where I was going. I also noticed that the cylinder head temperature was 4 degrees higher than it normally is. Are there any ideas what might be causing this?

techrep

iTrader: (1)

service the transmission and cooling systems and go from there.. you do not mention any maintenance performed on your 06 or mileage

technokami

The truck has 300000 KM on it, but maintenance has been kept up. The transmission pan was dropped and the filter and fluid changed just before I left. The thermostat is new and the coolant looks and tests ok. I'm adding a Mag-Hytec pan and new filter today and will see if the new fluid, filter and pan help any.

06_F150

There is a transmission thermostat inline with the cooling lines if you have the towing package (not sure if not). It is a rectangular block that both cooling lines go into between the trans and radiator/cooler. If this is stuck no fluid will reach the cooler.

technokami

The new pan, fluid and filter has helped a bit, but it still overheats. I have also done an oil change but that did not help anything. The ATF cooler warms up so it does seem like the thermostat is working but its still overheating.

06_F150

Maybe measure the temp to see if it's actually overheating or a sensor issue? Not sure of the best place to get a good temp measurement. I think there is a thread about adding an external gauge sensor.

technokami

I thought about that, but the higher CHT is what made me think its actually over heating.

Especial86

iTrader: (1)

What exactly are you getting for a CHT? What was it before..
The trans is definitely running too hot, you should be in the 145 to 160 range in most driving conditions. 180's max on a very hot day.
Check your fan clutch and make sure it's working,

technokami

The CHT used to stay between 186 and 188 but now it is around 188 most of the time and has gone as high as 196. The fan appears to be working, but I'm not sure how to test it other than make sure it appears to spin at a decent speed.