80 Series Transmission cooler lines, In and Out?

[Jenko]

G’day guys,
I’m in the process of installing an Auto transmission temperature gauge in my 1997 80 series. I’m trying to figure out which is the inlet hose to the auto trans cooler at the front so i can read off the hot side. Any help would be appreciated!

 

[jonheld]

G’day guys,
I’m in the process of installing an Auto transmission temperature gauge in my 1997 80 series. I’m trying to figure out which is the inlet hose to the auto trans cooler at the front so i can read off the hot side. Any help would be appreciated!

There is a temp sensor on the output of the transmission. Follow the line to the cooler.

 

[duece71]

I just replaced my old radiator and installed an aftermarket tranny fluid cooler (wholesale automatics). I traced the lines from and to the transmission. In the picture, hot fluid enters on the left and cooled fluid exits on the right. In my case, the exit is connected to the aux tranny fluid cooler and then goes back to the transmission. I put some orange and blue tape on the lines further back, sorry I don’t have pictures of those lines. Hopefully the pictures help.

 

[Marco Lau]

I tapped my transmission temp sender on the front of the oil pan closer to the dip stick. but the tranny output line prior to the radiator cooler should also work,,,

 

[Kernal]

With a 1997 US spec FZJ80 with the A343F ATM there are two ATF coolant lines running along the left side of the block, the top hard coolant line is the one leaving the transmission going to the right side of the radiator, the bottom hard line is the return.

If you look at the bottom photo above you can see a soft cooler line (hose) running from the vehicles left to right (hose with small yellow arrows), that's the top line when looking at the two lines as they run together along the left side of the block. HTH's.

 

[Gigem96]

With a 1997 US spec FZJ80 with the A343F ATM there are two ATF coolant lines running along the left side of the block, the top hard coolant line is the one leaving the transmission going to the right side of the radiator, the bottom hard line is the return.

If you look at the bottom photo above you can see a soft cooler line (hose) running from the vehicles left to right (hose with small yellow arrows), that's the top line when looking at the two lines as they run together along the left side of the block. HTH's.

If there is already a sensor there, is the measurement available on the OBD2? I cannot find a PID for it? I’m using OBD Fusion and I have dashboards setup for my 200 and 3rd gen that show it. I’d like my 80 to show also, but it’s not showing up in the obvious choices. Thanks.

 

[Malleus]

For some reason, Toyota never thought it needed to be available; even the 100 series doesn't have a signal that's exposed (at least I don't think it is). It's only used to trigger a system change; when the ATF temperature gets above the setpoint, the A/C cuts off and an idiot light comes on. Not the most helpful for what I would consider a critical event, but Toyota obviously thought the transmission was robust enough that it didn't merit consideration.

There is no PID, but you can write one. There is a thread in this forum from a year or two back about exactly that; you'll have to search for it. I may have bookmarked it; if I find it, I'll post an update with the link.
EDIT: see next post

The problem is finding the specs for the sensor that's in the cooler circuit. I've been unable to find anything, and I've looked. The service manual has a procedure for checking the sensor, but the data doesn't include the sensor range, that is to say, the output voltage curve compared to the ATF temperature. I think you'd need to know at least two points on that curve to write an accurate PID, and that's is assuming it's linear. If the curve isn't linear, you'd need the equation for the PID. Or you could measure the ATF temperature and output voltage under operation and fit a curve to the data points, and use that to write the PID. That's more work than I have idle time for, at the moment.

My thought was to put another sensor fitting at the point in the line where the OEM sensor is located, either before or after it, the choice is yours. You could use the same fitting that's there now (just couple a second one onto the line next to the existing Y-fitting the sensor is in), and supply your own sensor. That way, you'd have a sensor that you knew something about, and could write a PID for; the problem with this idea is that the output wouldn't be visible to the ECM; you'd have to wire the sensor to an aftermarket display. If you already had a Scangauge, or similar, that wouldn't be a problem. I don't, and I'm not going to have one, so I haven't pursued the idea.

You could also pull the terminals from the existing sensor's connector housing, and replace them with new terminals, after you crimped a second wire onto them. This would be, at most, a 10 minute job. This would provide an alternate output, the same way the previous idea would work, without the mess of having to install a second sensor. The problem is that you'd have the same situation you have now: you wouldn't have the specs for the sensor. But, if your Scangauge, or whatever, was smart enough, it may not be necessary for you to know. I haven't pursued this option for the same reason I didn't pursue the first: I'm not interested in adding a Scangauge.

Both ideas would work for someone who had an aftermarket add-on gauge, I would think.

 

[Malleus]

Here is all the information about custom PIDs you could ever want:
Transmission oil temperature for gauges

Make sure you refer only to the '98-'02 100 series posts. That transmission is very close to the A343F in the 80 series, it uses the same temperature sensor (89429-34010) and control logic. The '03-'07 100 series has a different transmission. It may, or may not be useful for this exercise, I haven't bothered to check.

Also, the '93-'94 80 series does not have the same ATF oil temperature sensor (89428-26030); it also has a different (A442F) transmission. Something to keep in mind.

Also, I'm currently using Torque Pro, but I'm considering Car Scanner Pro, based on the review @Mike NXP gave it.

 

[Gigem96]

For some reason, Toyota never thought it needed to be available; even the 100 series doesn't have a signal that's exposed (at least I don't think it is). It's only used to trigger a system change; when the ATF temperature gets above the setpoint, the A/C cuts off and an idiot light comes on. Not the most helpful for what I would consider a critical event, but Toyota obviously thought the transmission was robust enough that it didn't merit consideration.

There is no PID, but you can write one. There is a thread in this forum from a year or two back about exactly that; you'll have to search for it. I may have bookmarked it; if I find it, I'll post an update with the link.
EDIT: see next post

The problem is finding the specs for the sensor that's in the cooler circuit. I've been unable to find anything, and I've looked. The service manual has a procedure for checking the sensor, but the data doesn't include the sensor range, that is to say, the output voltage curve compared to the ATF temperature. I think you'd need to know at least two points on that curve to write an accurate PID, and that's is assuming it's linear. If the curve isn't linear, you'd need the equation for the PID. Or you could measure the ATF temperature and output voltage under operation and fit a curve to the data points, and use that to write the PID. That's more work than I have idle time for, at the moment.

My thought was to put another sensor fitting at the point in the line where the OEM sensor is located, either before or after it, the choice is yours. You could use the same fitting that's there now (just couple a second one onto the line next to the existing Y-fitting the sensor is in), and supply your own sensor. That way, you'd have a sensor that you knew something about, and could write a PID for; the problem with this idea is that the output wouldn't be visible to the ECM; you'd have to wire the sensor to an aftermarket display. If you already had a Scangauge, or similar, that wouldn't be a problem. I don't, and I'm not going to have one, so I haven't pursued the idea.

You could also pull the terminals from the existing sensor's connector housing, and replace them with new terminals, after you crimped a second wire onto them. This would be, at most, a 10 minute job. This would provide an alternate output, the same way the previous idea would work, without the mess of having to install a second sensor. The problem is that you'd have the same situation you have now: you wouldn't have the specs for the sensor. But, if your Scangauge, or whatever, was smart enough, it may not be necessary for you to know. I haven't pursued this option for the same reason I didn't pursue the first: I'm not interested in adding a Scangauge.

Both ideas would work for someone who had an aftermarket add-on gauge, I would think.

Sounds good. I think we’re on the same page with what I was already thinking. I was going to tap that existing sensor but wasn’t looking forward to the calibration. I’ve done it before in labs and programming the readers but not on the car. I was looking at tee’ing into that spot or cooler line with aftermarket Glow Shift Stubby and their inline tee. And one of their gauges on a a-pillar or headliner mount.