Where to install trans temp gauge

[MonsterBIlly]

I just put in my 4rth trans in 4 years. It's a 4r70w. I added an inline cooler as well as using the radiator. I did the external cooler first. That way the radiator can warm it is needed before it heads back, but the cooler will cool it before going to radiator if it's hot and hopefully won't add heat to the radiator.

I do not have a bung or anything in the trans pan. Is it cool to add a. Inline temp gauge to the cooling pressure line? Withholding that be faily accurate?

 

[Steve83]

According to Mark Kovalsky (a retired Ford transmission engineer), the only place to put a trans temp sensor is in the pressure test port on the trans. This is one of the places he mentioned it, but this discussion is about heavy E4ODs:

Slipping trans in od

I first noticed a slip in trans a few weeks ago I put the chip on extreme and hammered down it pulled good but I noticed when it got to 3rd(?) I wasn't picking up any speed. I just switched back to medium tow where I usually run. Today I hit the road all was normal until I merged onto the...

www.powerstrokenation.com

 

[Viperwolf1]

Fluid that has been pumped and cycled through the converter is not a good representation of overall fluid temp. This is where the fluid comes from that goes to the cooler. The temp there can be very high and it changes constantly with the load. Having a temp gauge in the cooler pressure port will freak you out because of the temps and not be a good indication of what is happening overall. Looking at cooler return temps can give you a false sense of security because that is the coolest portion of the fluid. Keep in mind that only a small amount of fluid gets sent to the cooler. Most of it is used to compress clutches and servos and lubricate things.

The pan contains the fluid which is about to be pumped throughout the transmission. It's temp changes more slowly and it doesn't experience the wild swings in temp based on what the converter is doing. The pan temp is what you want to measure. The 4R70W already has a temp sensor on the bottom of the valve body.

 

[bigmuddy]

Fluid that has been pumped and cycled through the converter is not a good representation of overall fluid temp. This is where the fluid comes from that goes to the cooler. The temp there can be very high and it changes constantly with the load. Having a temp gauge in the cooler pressure port will freak you out because of the temps and not be a good indication of what is happening overall. Looking at cooler return temps can give you a false sense of security because that is the coolest portion of the fluid. Keep in mind that only a small amount of fluid gets sent to the cooler. Most of it is used to compress clutches and servos and lubricate things.

The pan contains the fluid which is about to be pumped throughout the transmission. It's temp changes more slowly and it doesn't experience the wild swings in temp based on what the converter is doing. The pan temp is what you want to measure. The 4R70W already has a temp sensor on the bottom of the valve body.

So is it possible to tap into the OEM temp sensor in the 4r70w using an aftermarket gauge?

 

[Viperwolf1]

It would be if the gauge used the same range thermistor as the factory sensor.

 

[Broncobowsher]

Are you running a stand alone trans controller or the Explorer computer?
Both of those read the trans temp with the in-pan fluid sensor.

The convertor out will read hot most of the time. Not a great location. The cooler return is also bad. If you have restricted fluid flow through the cooler there will be lot of time for the fluid to cool as it slowly moves through. While the fluid in the transmission is trying to boil because of the lack of flow through the cooler.

As for Viperwolf's spec sheet, it gets even trickier then finding a gauge that has the same sensor range. You also need one that does not have a built in pull up resistor, or you get really trick and remove the pull up resistor. You would need a fully electronic gauge as well, none of the magnetic gauges will work as there will be no way to remove the pull up resistor (it is the magnetic coil that moves the gauge that is also the pull up resistor).

The test port is a pretty good spot, will read a little warmer than the pan temp. make sure the sensor isn't too long to the point where it can block the fluid passage. I have heard of that happening once.

If you want an aftermarket gauge that will just work and give numbers that match what the industry expects, put the sensor in the pan. I've been doing OEM testing for over 2 decades now. Pan temp is what we reference for transmission temp. We will also do cooler lines, both in and out, but that is to see how good of a cooler it is, not to judge how hot the transmission is running.

 

[Steve83]

It would be if the gauge used the same range thermistor as the factory sensor.

...it gets even trickier then finding a gauge that has the same sensor range.

It's even trickier than that, because the resistance through the gauge can affect the parallel resistance that the EEC reads, which would throw off its temperature reading. The gauge's resistance must be at least one order of magnitude higher than the sensor's.

 

[904Bronco]

Best place that I have found to put the Trans Temp sending unit... out of the way inside and out

 

[MonsterBIlly]

I do have a stand alone controller. I am using the us shift. It does read the trans fluid tmp buy I do not have it mounted where it's easy to see.
I have had a rough time with transmissions lately. So I want this one to last.

 

[Steve83]

Best place...

That's just convenient to mount it. The information you get from that location is not as relevant as you think it is.

 

[lars]

According to Mark Kovalsky (a retired Ford transmission engineer), the only place to put a trans temp sensor is in the pressure test port on the trans. This is one of the places he mentioned it, but this discussion is about heavy E4ODs

Fluid that has been pumped and cycled through the converter is not a good representation of overall fluid temp. This is where the fluid comes from that goes to the cooler. The temp there can be very high and it changes constantly with the load. Having a temp gauge in the cooler pressure port will freak you out because of the temps and not be a good indication of what is happening overall. Looking at cooler return temps can give you a false sense of security because that is the coolest portion of the fluid. Keep in mind that only a small amount of fluid gets sent to the cooler. Most of it is used to compress clutches and servos and lubricate things.

The pan contains the fluid which is about to be pumped throughout the transmission. It's temp changes more slowly and it doesn't experience the wild swings in temp based on what the converter is doing. The pan temp is what you want to measure. The 4R70W already has a temp sensor on the bottom of the valve body.

The test port is a pretty good spot, will read a little warmer than the pan temp. make sure the sensor isn't too long to the point where it can block the fluid passage. I have heard of that happening once.

If you want an aftermarket gauge that will just work and give numbers that match what the industry expects, put the sensor in the pan. I've been doing OEM testing for over 2 decades now. Pan temp is what we reference for transmission temp. We will also do cooler lines, both in and out, but that is to see how good of a cooler it is, not to judge how hot the transmission is running.

Best place that I have found to put the Trans Temp sending unit... out of the way inside and out

That's just convenient to mount it. The information you get from that location is not as relevant as you think it is.

I'm in the midst of installing a 4R70W transmission fluid temperature gauge along with said transmission. Seems that there is some disagreement about where to put the sensor. The pressure port ahead of the shift selector on the left side would be easy since it's drilled/tapped 1/8NPT. Sensor goes right in, done. One concern I have is that the Autometer sensor is twice as long as the OEM plug, see photo. I know nothing about the porting in a 4R70W case so I don't know if that's an issue. Could it block flow?

Meanwhile, Ford engineers apparently thought that measuring fluid temp at the valve body was a better location, at least for their requirements. I'm not interested in accessing the output from the OEM sensor (I'm controlling the transmission with an Explorer PCM), I will stick with the Autometer probe and gauge that I have. Adding a bung to the pan is only a little more work, I can make a bung and weld into the pan easily. So @Steve83 why is the reading from that location not relevant? For the others, what is scary about the pressure port reading, and will the sensor I have cause problems?

Thoughts?

 

[toddz69]

I've read a lot of Kovalsky's posts too over the years on the Ford trucks forums and in the posts I read, I came away with the conclusion that he thought the pan was a perfectly fine place to measure it. Perhaps I misinterpreted it.

Todd Z.

 

[nvrstuk]

Best place that I have found to put the Trans Temp sending unit... out of the way inside and out

That's exactly where I put mine... except mines on the drivers side.

 

[nvrstuk]

I'm in the midst of installing a 4R70W transmission fluid temperature gauge along with said transmission. Seems that there is some disagreement about where to put the sensor. The pressure port ahead of the shift selector on the left side would be easy since it's drilled/tapped 1/8NPT. Sensor goes right in, done. One concern I have is that the Autometer sensor is twice as long as the OEM plug, see photo. I know nothing about the porting in a 4R70W case so I don't know if that's an issue. Could it block flow?

Meanwhile, Ford engineers apparently thought that measuring fluid temp at the valve body was a better location, at least for their requirements. I'm not interested in accessing the output from the OEM sensor (I'm controlling the transmission with an Explorer PCM), I will stick with the Autometer probe and gauge that I have. Adding a bung to the pan is only a little more work, I can make a bung and weld into the pan easily. So @Steve83 why is the reading from that location not relevant? For the others, what is scary about the pressure port reading, and will the sensor I have cause problems?

Thoughts?

View attachment 921723

Once again I have no clue... but, I would sure make sure it doesn't block/obstruct any flow like you mentioned (and I think Broncobowsher). Might take some digging.

 

[rocknhorse76]

I’ve been running a small electronic sensor in the line pressure test port for a few years now with no issues. It reads very close to what is displayed on my Quick 4 controller too. I originally installed a bung on the side of the pan for that purpose, but decided to just use that as a drain instead.

 

[904Bronco]

I’ve been running a small electronic sensor in the line pressure test port for a few years now with no issues. It reads very close to what is displayed on my Quick 4 controller too. I originally installed a bung on the side of the pan for that purpose, but decided to just use that as a drain instead.

I have been doing the same with the 4R100 in my 2002 Superduty. The Factory gauge is of no use, as it never moves, and once it goes up, I have been told it is already to late...

 

[Viperwolf1]

I guess it's all about what you want to see. Do you want to see how hot a small volume of the hottest fluid in the trans is, or do you want to see how hot the majority of the fluid in the trans is?

 

[nvrstuk]

Back to the first post...

4th trans in 4 yrs? Just trying different ones in the same rig or four 4r70s burn up?

What is the style/design of your small cooler? Tube fin or stacked plate or OE or integrated cooling fan? Always curious.

 

[lars]

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.

 

[rocknhorse76]

I guess it's all about what you want to see. Do you want to see how hot a small volume of the hottest fluid in the trans is, or do you want to see how hot the majority of the fluid in the trans is?

Well, I have a readout of the pan temp on my Quick 4 already. I like to see just how much heat my converter is generating under load, which in the case of the one I grenaded last year, was a lot. I’m curious to see how the new Hughes converter I used in my recent rebuild works! Cooling isn’t an issue for me since I run 2 big external coolers. I suppose that if I only had one gauge, I’d probably go with the pan mounted sensor though.