Hello, been searching around for a while but couldnt really find a answer.

i just finished my ls swap, and i took it for a test drive.
i got a transmission temperatur sensor mounted in the transmission preasure port.
i know its not the best place, but i thought atlast it gives me an idea.

Have anyone compared the temperature reading from a preasure test port vs pcm or vs oil pan mounted temp sens?

my transmission was getting 230F to 240F on normal driving, which is to high, but ive learned that the reading may be off, but does anyone know «how much» off they will be?

should i be worried and upgrade the cooler?

 

I see about 180 F going into my cooler and 170 F coming out of it so yea, your fluid is quite hot. I'm guessing you have a high stall torque converter.

Rick

 

I believe it should not go above 180.

 

That is certainly true for normal driving. Hot-lapping at the drag strip I've seen 195F, but typically 160F in normal driving.
Your 230F indicates a serious problem which will quickly ruin your trans. Even if you are only using the stock cooler, I wonder if your cooling lines are restricted.
With any higher stall converter an external cooler is very highly recommended. And ideally it should be plumbed with AN-6 lines to ensure reliability and durability. Plenty of posts here on exactly what to buy for that.

 

I think you guys misunderstand my question, or the question was not clear.

I»m not sure if the transmission is actually as hot as the temp gauge says, since i use the preasure test port and the car does not go i to limp mode.

i was wondering if anyone has compered the values from pcm or a seperate oil temp in the transmission oil pan.


i use an6 lines and a stock 1972 pontiac radiator, which should i teori be enough.

 

Go to Harbor Freight and take your 20% off coupon to buy an infrared temperature gun. Aim it somewhere dark in color on your transmission for a more accurate infrared temperature. This will give you another data point about how hot your trans really is.

Rick

 

Yea, and it wasn't that far off. That 230 - 240 reading came from somewhere. The case and everything around that port should never be 240 degrees.
Hopefully your gauge is off because if it's accurate and something is 240 degrees you have a big problem.

 

There are plastic parts inside, you need to get it checked out, I got a cooler and helped alot.

 

What coolor are you running? Is it a standalone cooler or ran along a stock cooler?

Where is the cooler mounted?

 

That is just a very minimal "cooler" which is only a short 10" tube going through the hot radiator fluid. It cannot cool lower than the temperature of the radiator fluid, which is likely 180F+ with a standard thermostat.
Yes, I see your point that fluid coming out of the trans might be quite hot, but for performance use it needs to be cooled well below 180F.
Its the temp of the internals of the trans which is important; hence B52bombardier1's suggestion to use a IR thermometer on the pan and case of the trans to give you a useful reading.
Also, many (most?) scanners show the trans temperature as reported to the PCM. Or perhaps try one of those $40 "smart" gauges which lets you display one or more values from the PCM.

 

I like everything said here. I didn't realize you stated the cooler you were using. Not only is that not great, you'll see a huge benefit by NOT going through the radiator. Pick up a stacked plate design from a well reputable company like B&M or Hayden. Where you mount the cooler is also extremely important.

 

This is not necessarily true. Fluid-to-fluid is a much more rapid method of cooling than air-to-fluid, so if your engine cooling system is such that you're maintaining a lower coolant temp than what exits your transmission, then an internal radiator trans cooler can certainly be a benefit for some rapid initial cooling. Of course, this likely isn't going to be the case if you have a relatively high temp t-stat and factory fan settings (for modern vehicles with e-fans). Several folks have documented the benefit of running through the internal cooler first (assuming relatively low coolant temps), then running into an aftermarket external cooler. But yes, if you're having a problem (or not able) to get the engine coolant temps into a beneficial range, then omitting the internal radiator cooler should be considered.

 

True. Definitely differs per application/issues. On my 98 Z28 I was seeing 200ish Temps through my pcm. After I bypassed and ran standalone I'm now seeing 175-180. Just depends. Location of the cooler makes a big difference as well. Hopefully OP can let us know where it is. I think an upgrade in cooler would be of great benefit as well.

My readings were/are through my PCM with an interceptor. *

 

The 4l60e has an internal temperature sensor for crying out loud.
A sensor already submerged in the pan

If you have a factory GM PCM, I have a thread showing how to find the trans temp. If you have HPTuners for your swap...it's even easier

If you have an aftermarket computer that doesn't use it, it would be quite easy to find the resistance table and you could literally use a multimeter to measure the resistance and find your temperature

 

So how? I got Terminator X myself but could still use the info if I knew the range of the sensor output.

 

It's rocket science, and top secret so be very very careful with this information.

https://atracom.blob.core.windows.ne...ear/atb269.pdf

 

 

Not secret at all...I just didn't want to go digging at that moment to find it.
Just like the post above me says...read between pins L and M and find the resistance.
If you want to set it up in the holley, use a temp sensor input and scale the resistance table values to match above.
Easy