Which to trust?

[e280x]

So doing the ATF service.
Carried out the procedure of filling the sump with 7L of oil.
Had the car running for around 30 mins.
iCarsoft was showing 45 degrees while the infrared thermometer was showing around 32 degrees.

So who do I trust? Where does the iCarsoft get its reading from. Like, where is the transmission temperature sensor?

Problem is when I went to drain the excess hardly anything came out.
When draining the origional fluid I managed to spill some so not exactally sure how much came out.

Advice, experiences, tips etc would be much appreciated
Thanks.

 

[markjay]

I would go with iCarsoft, on the premise that it reads the same sensor that STAR would read, and this is what the MB procedure is based on.

No idea where the sensor is located though.

 

[steveq]

Like above, I suggest that you trust the iCarSoft for the temp.

If you drained the sump and the TC, the full amount should be 9 litres.
Get the gearbox up to temp and then let the oil come out of the sump. It should gush out and then slow to a splutter. Then put in the sump plug.
There are some good YouTube videos on this which show the oil coming out and then just spluttering.

 

[e280x]

Makes sense, I'll go with that.
Thanks.

 

[slade1]

Cheap infrared thermometers are probably inaccurate.