I installed a temperature gauge on my E4OD tranny (92 F250 2WD). This is a mechanical gauge with the sensor installed at the tranny Line Pressure Tap (the "test port").



The probe is too large to fit inside the test port, so I attached it using some brass fittings that allow fluid to fill in around the probe.



I drove the truck around a bit today (about 40-45F or so outside) and when I arrived home the gauge read about 145F.



I borrowed a handy IR temperature sensor and checked a few points on the tranny to see how accurate the gauge might be. First place is up on the case, somewhat near the shift lever input, but definitely up on the case, 158F.



As I made these readings, the truck was idling, so the temperature creeped up over the 10 mins or so that I probed around. Near the thermal sensor for the gauge itself, I read about 167F.



I checked the gauge again, it now read 150F



My truck has an auxilliary (factory) cooler for the E4OD tranny. I read the inlet side of the cooler and saw 154F



and on the outlet side of the cooler I read 133F



Indicating about a 20F drop across the cooler. I did this in my garage with the truck idling.

I read the pan/case just below the temperature sensor. The sensor is wrapped in a red rag, to try and insulate the sensor assy from any airflow. 146F. Just about the same as the gauge reading.



I pointed the IR sensor at the bottom of the pan, and read 143F, lower than the gauge at the time of reading the pan (gauge now read just above 150F).




Finally, I pointed the IR meter at the exhaust. First the pipe near/behind the tranny, just ahead of the catalytic converter.



And here, pointed at the exhaust just below the connection to the header (near the block).



I am pretty confident after this exercise that the gauge reads fairly close to the average temperature of the pan, the body, and the fluid.

 

Nice write-up with pics!

 

ideally your trans temp wants to run @ 170-180 degrees (at pan/e40d's test port.)
i had to install an aux oil t-stat in front of my aux air cooler,to help bring temps up closer to perfect.winter was really bad,as i couldn't hardly get the old gal up to at least 150 in any reasonable amount of time/miles.when the converter locks,these e40d/modern trans sure run cool.

 

I had driven about 30-35 miles before making these readings. I've had this sensor in for about 100-150 miles. In that time, the highest I have seen the gauge is 165. I am hoping to see it go that high again, and then I can rescan the temperatures with the IR reader again.

At ths point, I am not suspecting anything amiss, I am simply doing some experimentation to see what temp the tranny runs. I have no idea (yet) what the max operating temperature might be.

 

you can help scoot things along by blocking off your aux cooler with a sheet of cardboard.that's what i did in the winter before installing the t-stat.

 

As it turns out I already have a bit of blockage at my radiator. Which, I think I will probably remove for use during the spring/summer...good idea, no?