BlaineBug

You're absolutely right although a PID should work regardless, as it works for ScanGauge and a variety of other monitoring tools and products as well.

I have a cheap ELM327 Bluetooth adapter that I've had since 2017, and still on Lite version.

Besides inputting weight and displacement in settings there is not any more to enter.

Yes, I did. PID for transmission temperature is 221940.

I see nothing of the sorts in my app.

Also my transmission temperature PID is not working - the PID code from the preloaded custom GM PIDs is identical to the PID I found online for creating a custom gauge.

Your display looks vastly different than the one I am seeing in Torque Lite.

EDIT - Torque Lite has a full list of custom PIDs for General Motors already compiled, although you can still add your own custom PIDs as well. These are buried in the settings and you have to add them in order to be able to insert them as a gauge. I am not seeing an oil temperature PID though already installed, unless you might happen to know of the custom variables to enter for that gauge?

I only ever used one custom PID for transmission fluid temperature in my Crown Victoria. I also bought a second cable so I could easily remove the device for performing external diagnostics, yet have the original cord tucked away nicely in my dash for a seamless OCD-esque installation in my vehicle. However when I sold that car I sold the scangauge shortly thereafter and bought the ELM327 Bluetooth dongle for diagnostics.

According to Torque Lite, coolant temperature was ranging anywhere from 190-197' F (depending on engine load, idling, cruising, etc.) when the dash gauge was reading ~210. I was hoping for more accuracy given all of the bells and whistles, especially with a digital trans temp readout on the DIC. Torque Lite also doesn't display transmission temperature or oil temperature unless there's a special method to add these gauges I am not aware of, so I can't verify if the DIC display would match a scan tool or not. Intake air temperature was reading around 100' and ambient outdoor temperatures were around 80'. Unfortunately I didn't check the coolant temperature with my tool before installing the alternate thermostat, so I have no data to compare my findings with.

I'm not sure what setup it has for cooler routing. At any rate I'll check my scan tool for water temperatures. I noticed your ScanGaugeII displays "water temp" AND "engine operating temp"? Where is the second reading taken?

Was mentioning 2 different "thermostats" here, the transmission cooler bypass and the engine coolant thermostat. This discussion now includes 2 different mechanicals.

Not sure about 10 speed but the 6 and 8 speed now have an OEM GM revised coolant thermostat bypass assemblies that lowers the transmission fluid temperature by 30-40 degrees Farenheit under now-towing conditions, yet still provides thermostatic properties for ensuring that the transmission fluid warms up quicker and maintains a minimum in colder climates.

To report after more than a few days of use, I'll say that visually and using the coolant temp gauge on the dash, there is definitely no "noticeable" difference that is significant in regards to the operating temp of the vehicle which always seems to be just slightly to the left (lower than) 210' Fahrenheit. If you're looking to lower transmission temperatures obviously your best route is either bypassing/[plugging the factory thermostatic properties if you live in a warm climate or installing the newer revised lower opening temperature thermostat for the transmission cooler lines if you live in a cold climate and still require low-end transmission fluid temperature moderation. As has been my belief for decades now, a coolant thermostat will not lower temperatures because the thermal output of the motor and the cooling properties of the radiator will always be consistent, and once the thermostat is fully opened, it's essentially taken out of the equation regardless. The new versus old coolant thermostat opening temperatures of 194' versus 207' aren't significant either, a 13 degree difference, with no noticeable change in operating temperature as per DIC gauge cluster. However, installing the revised transmission cooler thermostat will see noticeable improvement of 30-40 degrees Farenheit on average. Which leads me to believe that typically with no undue stress, hard acceleration, or towing, the transmission was being kept HOTTER on purpose than it's true default operating temperature with the factory transmission fluid cooler thermostat. The engines however are probably designed to be run around 200-210 as they have been for decades. Even in the 1990s engines were designed to run optimally somewhere between 190-210 degrees Fahrenheit. And apparently they still do, if not slightly hotter. Installing a coolant thermostat that opens EARLIER will not result in a cooler operating temperature at all. An engine produces a whole hell of a lot of heat regardless due to the combustion process and friction as well. A transmission only puts out heat due to friction, so when you're sailing along smoothly and not constantly accelerating and shifting through the gears (slipping = friction) you will see lower operating temperatures during this time of reduced operational stress.