Autometer trans temp VS. Termy Scan Gauge trans temp

[farm boy]

I have the regular old Auto meter mounted in my pillar. Gauge is a few years old at least. While scrolling through the different stuff the scan gauge reads, I noticed a 30-40 degree difference in the two gauge readings. The Auto meter is showing less. Any reason for one to be false? Auto meter gauge sending unit is in the test port on the side of the trans.

Also, is the scan gauge EBP reading accurate? After subtracting the 15 psi or so for air pressure of course.

 

[CSIPSD]

The reason the trans temp gauge and the PCM are reading different is the location of the temp sender. The PCM gets its reading from deep inside the tranny. The gauge gets it from the test port.

 

[PsRumors]

30 - 40 degrees difference? WOW. When running a CTS I was told the CTS would read 10 - 15 degrees higher due to the sensor placement (like CSIPSD) stated.

On the CTS my trans never got above 154.

 

[farm boy]

Thanks guys. I kinda don't trust the Autometer anymore...

I guess Ill have to keep one of the the Scan Gauge readings on the trans temp when towing.

Any Trans temperature gauges on the market that read directly off of the PCM that would piggy back off of an OEM sensor?

 

[CSIPSD]

Nope... Get an Isspro and forget about it. Problem with using the PCM reading is when you post up a tranny temp, everyone else will be cooler then you.

 

[Tom S]

30 - 40 degrees difference? WOW. When running a CTS I was told the CTS would read 10 - 15 degrees higher due to the sensor placement (like CSIPSD) stated.

On the CTS my trans never got above 154.

That is about my experience as well for the temp difference.