Can I install this temp sensor in Ford E40D test port?

Over on a Ford Forum there is a fellow who claims he was an automatic transmission engineer from 1988-2007.

https://www.ford-trucks.com/forums/1544279-can-i-install-this-temp-sensor-in-ford-e40d-test-port.html

He advises putting the sensor in the test port.

Now had originally leaned towards installing it in the transmission output line, as I agree - this is the most accurate and accessible place to measure the worst-case temperature of the transmission fluid. And I do agree that the temperatures will be hotter on the output line first before the case/test port catch up.

But I believe that the test port will suffice. In the RV, it's generally long-haul traveling and in short order the transmission itself will match the temperature of the fluid going through it.

The important thing to realize if you use the test port, I think, is that test port temperatures will lag fluid temperatures. So if you start seeing hot temperatures via the test port, realize that actual fluid temperatures are probably running hotter still.

Ultimately I went with the test port because it was super easy and did not require cutting any transmission cooling lines.

I have also ordered a 1/4" Tee and will see about putting it right in the side of the transmission where the output line currently goes, and then threading the output line into the tee and putting a sensor into the side of the tee via a 1/4 - 1/8 adapter, if it will fit. If it works, I might install another temperature gauge for fluid output temperatures and see how the two locations track one another.

Steve

LarryJM wrote:

RLS7201 wrote:
The best way to monitor transmission temperature is the fluid line leaving the transmission. Which comes from the torque converter. That way you see the hottest fluid.
On your E4OD that is the front line on the right side.Picture of sensor in hot line.

Richard

I DISAGREE, the temp out of the TQ can vary WILDLY and is really not useful as a single value variable. There are no standards to my knowledge for that temp to compare temps to for monitoring. The important temp is what the actual tranny is operating at which is the sump temp and the test port the OP is talking about is a common place to measure that temp.

Larry

But the life of the transmission fluid is determined by time at the highest temperature. Which you won't see in the test port or pan.
Yes testing the temperature of the fluid right out of the torque converter will vary when the torque converter clutch is unlocked but when the clutch is locked the temperature will be stable.
See temperature chart ver mileage.

Richard

I ended up going and getting a male/male 1/8" fitting, and a female/female 1/8" fitting, and making my own 1/8" M/F extender. It is now fitted into the test port of my transmission.




Steve

I used the E40D test port on a previous 1995 F53 and found the temp readings to be quite reliable for monitoring the internal conditions. When I had a remanned E40D installed prior to installing the gauge, I noticed that the tech used that port for temp testing as well as pressure testing. He recommended using it for an aftermarket gauge as well. As to the temp sensor the OP is considering, I can only suggest that he probe the port to see if there's enough depth for it.

Just install an oversize transmission cooler and be done with it.

My RV already has a transmission cooler. I have been having some engine overheating problems (crusty radiator is being replaced) and as part of the project I have installed a dual temperature gauge in the dash. I have already wired one sensor into a new thermostat housing neck but am wondering how to do the transmission.

I DISAGREE, the temp out of the TQ can vary WILDLY and is really not useful as a single value variable. There are no standards to my knowledge for that temp to compare temps to for monitoring. The important temp is what the actual tranny is operating at which is the sump temp and the test port the OP is talking about is a common place to measure that temp.

There is tremendous debate on this on the internet. The test port is obviously the easiest place to put the sensor.

But it seems to me that the worst-case measurement would be right as the fluid exits the transmission. The fluid will never be hotter than it is right there.

But on the other hand, you don't constantly want to be keeping your eye on a gauge that keeps changing value to see if it is going to overheat this time. Maybe a more stable output like the test port is a good idea.

I just have to find out whether this GlowShift sensor needs an extender for the E40D test port.

Steve

Just install an oversize transmission cooler and be done with it.

RLS7201 wrote:
The best way to monitor transmission temperature is the fluid line leaving the transmission. Which comes from the torque converter. That way you see the hottest fluid.
On your E4OD that is the front line on the right side.Picture of sensor in hot line.

Richard

I DISAGREE, the temp out of the TQ can vary WILDLY and is really not useful as a single value variable. There are no standards to my knowledge for that temp to compare temps to for monitoring. The important temp is what the actual tranny is operating at which is the sump temp and the test port the OP is talking about is a common place to measure that temp.

Larry

The best way to monitor transmission temperature is the fluid line leaving the transmission. Which comes from the torque converter. That way you see the hottest fluid.
On your E4OD that is the front line on the right side.Picture of sensor in hot line.

Richard