Where to install trans temp gauge

[rocknhorse76]

So fun to get everyone riled up

I think I will put it in the pan, easy enough. Just need to wait until I figure out what the transmission crossmember will look like.

Hey Lars, thanks for the reassurance on my choice of converters btw! And FYI, it works great with my build, so it should be great for yours too!

 

[lars]

Hey Lars, thanks for the reassurance on my choice of converters btw! And FYI, it works great with my build, so it should be great for yours too!

My pleasure, and I look forward to (someday) learning how it works. Do you know what, in mathematics, an asymptotic function is? Right now it seems like that pretty well describes my build. I keep getting closer but never seem to get there.

 

[rocknhorse76]

My pleasure, and I look forward to (someday) learning how it works. Do you know what, in mathematics, an asymptotic function is? Right now it seems like that pretty well describes my build. I keep getting closer but never seem to get there.

Haha that’s how mine was until Brian cracked the whip on me

 

[ba123]

Yeah, DO NOT put in in the cooling line unless you want to know what temp your converter is putting out.

I made this mistake. I constantly see temps in the 250-260 range and I'm sure it'll get higher as I go for longer drives and push it harder. It's not the temp you need to know.

As @Broncobowsher mentioned, it reads hot and you should put the temp sensor in the pan.

I've read about putting it in the pressure port as well, but yeah, that's a small port and doesn't make any sense to me and I have a pressure sensor in there anyway.

I plan on putting a pan sensor in as well the next time I remove my pan.

If you want the best of both, it might be good to know the temp out as well as the pan, but honestly, the inline temp was a pima and wish I'd realized this wasn't ideal before. Wasted SO much time on this.

Once I do put a pan sensor in, I'll install a toggle switch for the same gauge to read the TC out temp as well as the Pan temp.

 

[nvrstuk]

I think you're gonna love the Hughes converter long term. Heck, you've already put a couple hundred on it... report back!

 

[ntsqd]

I put mine in the pan. I don't care what the temp is going out to the cooler. I don't even care what the temp is coming back from the cooler. I want to know what the temp of the fluid about to be sucked into the trans to cool and lubricate it, is. If that is too warm then all of the other temperature sampling locations no longer matter.

 

[Steve83]

why is the reading from that location not relevant?

For the reasons Mark explained in that linked thread and a few others. I don't have them memorized, but they made sense to me last time I read them, so that's where I put the sensor in my '97 F250HD's E4OD.

 

[lars]

For the reasons Mark explained in that linked thread and a few others. I don't have them memorized, but they made sense to me last time I read them, so that's where I put the sensor in my '97 F250HD's E4OD.

Fair enough, Mark is obviously an expert on automatics, but there are only 3 replies by him in that forum thread and other than mentioning that the pressure port is the most accurate reading, he doesn't really explain anything. For example, why putting a sensor in the pan could be misleading. And no, I haven't done a search for other input from him. This isn't the sort of thing that gets me too wrapped around the axle.

I may well try putting a sensor in the pressure port just to see what it reads, since it's so easy. But I am concerned about possible port blockage with the longer-than-OEM probe.

 

[ba123]

I think it would be interesting to know what it reads out of the pressure port.

If you want to try and not block anything, you could easily put something like I did on the pressure port.

I did in order to put a pressure sensor, but it shouldn't be terribly different for a temp manifold, but the thing is that a temp sensor needs more depth and I don't see how it's going to be accurate. It will just read the temp of the case and not the temp of the fluid like you need.

I just don't see how that's going to be accurate, but again, I'd be curious to know for sure.

 

[Steve83]

...why putting a sensor in the pan could be misleading.

Same reason the ECT and temperature gauge senders are not in the radiator or heater core.

But I am concerned about possible port blockage with the longer-than-OEM probe.

There was no OE probe, so there's nothing longer, and I don't think length matters, anyway. But if you get the truck running & driving first, and then install the probe, you'd know instantly if the trans behaves differently, so there's no risk. If you start it up with the probe & it doesn't shift right, you'll know before any damage occurs.

...it shouldn't be terribly different for a temp manifold...

Temperature only works where there's flow - not in a manifold. So yes, it's very different from pressure.

 

[lars]

Same reason the ECT and temperature gauge senders are not in the radiator or heater core.

There was no OE probe, so there's nothing longer, and I don't think length matters, anyway. But if you get the truck running & driving first, and then install the probe, you'd know instantly if the trans behaves differently, so there's no risk. If you start it up with the probe & it doesn't shift right, you'll know before any damage occurs.

Temperature only works where there's flow - not in a manifold. So yes, it's very different from pressure.

Still a non-answer. Giving credit where credit is due however, you mentioned Mark Kowalski. I went looking for other posts by him and found this old thread that exactly addresses the question:
https://www.ford-trucks.com/forums/756728-test-port-vs-pan-temperature.html
See Mark's reply in post #11. That thread is almost 16 years old so obviously it's been a topic of discussion for awhile. And I discovered that that forum has a lot of useful transmission info. Helps that the trucks under discussion there came stock with these automatics, whereas here they are still kind of a novelty.

As for the probe length, if you had looked at the photo I posted comparing the OEM plug to the temp sensor I have, you'd see that the stock plug has an extension on it. Which I realize is probably just a lead-in so production workers don't strip the plug when installing it. But it's half the length of the sensor, and not knowing what's inside the port, I didn't want to randomly screw something in there and risk blocking a passage. So, I removed the pressure port plug on my 4R70W today to have a look. Probed the port with a small pick and a flashlight. There is clearly a large volume inside the case and no way that the sensor I have will block anything.

Bottom line, given Mark's advice and the fact that installing the sensor I have into the pressure port is a lot less work (no weld-in bung required) I've installed it there.

 

[ba123]

Still a non-answer. Giving credit where credit is due however, you mentioned Mark Kowalski. I went looking for other posts by him and found this old thread that exactly addresses the question:
https://www.ford-trucks.com/forums/756728-test-port-vs-pan-temperature.html
See Mark's reply in post #11. That thread is almost 16 years old so obviously it's been a topic of discussion for awhile. And I discovered that that forum has a lot of useful transmission info. Helps that the trucks under discussion there came stock with these automatics, whereas here they are still kind of a novelty.

As for the probe length, if you had looked at the photo I posted comparing the OEM plug to the temp sensor I have, you'd see that the stock plug has an extension on it. Which I realize is probably just a lead-in so production workers don't strip the plug when installing it. But it's half the length of the sensor, and not knowing what's inside the port, I didn't want to randomly screw something in there and risk blocking a passage. So, I removed the pressure port plug on my 4R70W today to have a look. Probed the port with a small pick and a flashlight. There is clearly a large volume inside the case and no way that the sensor I have will block anything.

Bottom line, given Mark's advice and the fact that installing the sensor I have into the pressure port is a lot less work (no weld-in bung required) I've installed it there.

Thanks for finding that!

Now I wish I'd gotten a combo pressure and temp sensor.

Oh well. I'll enjoy watching my 250° output from the TC until I do something else.

 

[Steve83]

...if you had looked at the photo I posted comparing the OEM plug to the temp sensor I have...

I did look - it's irrelevant (as you eventually confirmed for yourself) which is why I said it doesn't matter.

Still a non-answer. ...
...
Bottom line, given Mark's advice and the fact that installing the sensor I have into the pressure port is a lot less work (no weld-in bung required) I've installed it there.

So you've confirmed that the brief, direct answer I posted last year (before you asked) was a yes-answer, which makes all my replies to you reiterating that original answer also yes-answers. Your question was a non-question.

 

[lars]

I did look - it's irrelevant (as you eventually confirmed for yourself) which is why I said it doesn't matter.

So you've confirmed that the brief, direct answer I posted last year (before you asked) was a yes-answer, which makes all my replies to you reiterating that original answer also yes-answers. Your question was a non-question.

Except your brief answer was unhelpful and condescending, like a parent telling a kid to believe something because you said so. But you accidentally left a clue that led to information that was actually useful.

 

[Steve83]

Nothing I post is accidental. And if it was useful, then it was helpful; so brief was enough. But I never said to believe what I said - I said to believe what Mark said. So the condescension wasn't coming from me - you just read something that wasn't there.