Temp sensor

[PlayingWithTBI]

Hey @Ethan Burdette - like your Custom Title, LOL!

 

[Joe Dirte]

Hey @Ethan Burdette - like your Custom Title, LOL!

Thanks. Gotta keep up the appearances.... Keeps people guessin.

 

[someotherguy]

I've seen where guys cut a hole in the pan and weld a bung for the sensor there. That's better than using the 1/8" NPT test port where your sensor is not in the flow of the fluid. I don't know if splicing in to the internal sensor will cause issues with its controls.

While I might have agreed with the test port being a less-than-ideal spot, I've tested it extensively and using the aftermarket gauge sender in the test port vs. reading all over a thoroughly worked-out transmission using an IR temp gun with a "max read" function, scanned everywhere from torque converter, case, pan, cooling lines, everywhere - about a 1 degree variance from the gauge reading. First one I did like this was on a 4L80E in my '96 dually wrecker. Ran it stupid hard to get it nice and hot before checking it. 100% confidence in that location for the sender, for me, anyway. Did another one later on a 4L60E in my '94 C2500LD.

Whenever I do my trans cooler lines (rusty) I am planning to put in a T fitting where the fluid enters the external cooler by the radiator. That will capture the oil temp close enough.

Every splice into a cooling line is a potential leak. Now if you're talking about a solid fitting so there's no additional clamps or hose pieces, I'll retract that statement. I just know more than one person that got a little careless hooking up an aux trans cooler for example and the hoses blew off under load and wasted their transmission in a hurry.

Back to Ethan: short story - the test port worked perfectly for me in more than one application. It's the little pipe plug in the driver's side of the transmission case above the shifter.

Richard

 

[alpinecrick]

Whenever I do my trans cooler lines (rusty) I am planning to put in a T fitting where the fluid enters the external cooler by the radiator. That will capture the oil temp close enough.

This is the best bet for an accurate reading.

Or on the outlet side of the external cooler-then a guy would know that his cooler is up to ***** and the fluid entering the trans is sufficiently cooled.

 

[alpinecrick]

I have been told on the 4L60E's the test port is an "arctic zone" and reads 20-30 degrees cooler than the actual fluid temp because the fluid only "splashes" the sensor.

 

[someotherguy]

I have been told on the 4L60E's the test port is an "arctic zone" and reads 20-30 degrees cooler than the actual fluid temp because the fluid only "splashes" the sensor.

I'm no student of fluid dynamics but that really sounds hard to believe. My personal, uneducated opinion. And, not what I've observed in real-world practice.

Richard

 

[PlayingWithTBI]

I guess if that port isn't in the flow through the trans, it would be slower to equalize temperature with the rest of the system but eventually get there? Just guessing, I have no personal experience but, I do want to install a temp sensor someday.

 

[Joe Dirte]

While I might have agreed with the test port being a less-than-ideal spot, I've tested it extensively and using the aftermarket gauge sender in the test port vs. reading all over a thoroughly worked-out transmission using an IR temp gun with a "max read" function, scanned everywhere from torque converter, case, pan, cooling lines, everywhere - about a 1 degree variance from the gauge reading. First one I did like this was on a 4L80E in my '96 dually wrecker. Ran it stupid hard to get it nice and hot before checking it. 100% confidence in that location for the sender, for me, anyway. Did another one later on a 4L60E in my '94 C2500LD.


Every splice into a cooling line is a potential leak. Now if you're talking about a solid fitting so there's no additional clamps or hose pieces, I'll retract that statement. I just know more than one person that got a little careless hooking up an aux trans cooler for example and the hoses blew off under load and wasted their transmission in a hurry.

Back to Ethan: short story - the test port worked perfectly for me in more than one application. It's the little pipe plug in the driver's side of the transmission case above the shifter.

Richard

I just got home from a nice 4 hr ride in my wagon. 6 counties and cruisin in comfort. I'll check that port again since it's daylight and I'm sober, for now n get back in here

 

[alpinecrick]

I'm no student of fluid dynamics but that really sounds hard to believe. My personal, uneducated opinion. And, not what I've observed in real-world practice.

Richard

Richard,
Can't speak for the 4L80E, not even sure if their is a test port on that trans.

But the original owner of my 97 K1500 worked at the GM dealership and installed a trans temp gauge in the test port in his 95 Suburban w/ 4L60E. When he saw 160-170 degrees even climbing the pass at 8k-9k feet (where the thinner air doesn't cool as well) he talked to the mechanics and they said "no way can temps be that low". So he moved the sensor to the inlet of the auxiliary cooler in the radiator. Climbing the same pass his temps read 190+.

I want to install a temp gauge on both my 96 and 97 K1500's. I'm thinking about buying a fittings for the test port and a t-fitting (and yes I'm am concerned about leaks too) and temporarily install both trans temp gauges in one of the trucks to see if there is a "real time" difference between the two locations. I may even buy two t-fittings and temporarily install them in the inlet to the auxilary cooler and outlet line of the external cooler.

Although we can't believe everything on the internet (yours truly included, I guess .....) I have read where other guys have moved the sensor fittings and have had different temp readings.

 

[Joe Dirte]

Just to be sure.... Is this the test port incase I put it here?

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