Best location for trans temp sensor? - Diesel Forum

Runboy · 03-07-2007, 10:57 AM

I was hoping to get a few oppinions on the best location for a transmission fluid temp sensor with the E40D. Previous owner had one tapped into one of the lines heading up to the front of the truck. Wasen't working so I removed it at the time.
Seems like there must be a port on the case that would be better?
Mike

Casey_1 · 03-07-2007, 11:46 AM

There is a port on the driver's side of the trans, towards the front, just above the pan. There's a black hex head plug from the factory. Remove it and install the probe.

DSBlack · 03-07-2007, 02:10 PM

That is where I have mine. I have since heard that this is not the best choice? It was recomended to place it in the pan or the line to the cooler.

Casey_1 · 03-08-2007, 04:26 PM

[ QUOTE ]
I have since heard that this is not the best choice?

[/ QUOTE ]
Everyone has their opinion on the best location. My opinion is the test port is the best place.

icanfixall · 03-08-2007, 07:23 PM

Mine is in the "test port" and I have many-o-miles on it without any trouble.

Runboy · 03-09-2007, 01:54 AM

Only downfall I can think of to having it in the case is that you may be getting more of a "case temp" reading than "trans fluid temp".
Any thoughts?
I would prefer it in the case rather than dangling around in the middle of the cooler line, unless the verdict suggests that the temp reading is that much more accurate.
Mike

DSBlack · 03-09-2007, 01:58 PM

I have been asking a lot of questions, I have had a lot of trans issues, and never had the trans hot. I have the gauge at the port mentioned.
I am not a trans guy. I know very little about them. So I am by no means an expert.
I was told that the flow of the fluid is low in that area, and if the temp increases rapidly, then falls off, you may not see that in this port? I do not know if they are correct or not. I have not moved mine from this port, but I do plan to.

Casey_1 · 03-09-2007, 04:18 PM

[ QUOTE ]
I am not a trans guy. I know very little about them. So I am by no means an expert.

[/ QUOTE ]
I am a trans guy. I know a lot about them. People that I work with consider me a trans expert among transmission people, and transmissions are what I've worked on for almost 20 years.

[ QUOTE ]
I was told that the flow of the fluid is low in that area, and if the temp increases rapidly, then falls off, you may not see that in this port?

[/ QUOTE ]
True, but so what? Is that what you want to know? Do you want to know the temperature of the transmission or the maximum temperature the fluid sees for a short time when the torque converter unlocks under load? I like to know the overall trans temp, not the transient spike when the converter unlocks. If I were to have multiple trans gauges I'd have the secondary one in the line, but in my not so humble opinion the port is the right place to put the sensor.

But you don't have to believe some anonymous person posting on the internet. I could be all wet, but I don't think so. [img]/ubbthreads/images/graemlins/grin.gif[/img]

MyDTpickup · 03-09-2007, 08:40 PM

well was the port put there for this reason or not?

Casey_1 · 03-09-2007, 09:12 PM

It was not put there to measure temperature. It was put there to measure line pressure. The Ford shop manual refers to this port for trans diagnostics. The tech screws a pressure gauge into the port and runs a series of pressure checks.

DSBlack · 03-10-2007, 01:21 PM

I did not mean to offend anyone. I have learned a lot from everyone here. Just passing on some info about what I heard/learned after loosing 4 trans in 40,000 and never having one overheat on the gauge.

swervn69 · 03-10-2007, 01:34 PM

The best place would be in the line exiting the transmission heading to the cooler ( front Line) because most of the heat generated in the transmission is in the torque converter. This line comes directly from the converter out to the cooler and then back to the rear lube circuit. Locating the temp probe here will allow you to see if your converter is slipping which is usually the first thing to overheat the fluid. IMO this is the only place to locate the trans temp gauge and am about to put mine there. I am a Ford certified diesel tech as well as an instructor in a local technical institute and this is the only place that makes sense to me.