Originally Posted by NuthatchBC
How do you know what the temperature of the oil is? We have a 2012 Tacoma and there are no numbers on the gauge. I just watch it to make sure it stays in the normal range.
I checked the manual, and it looks like the only temperature gauge in a 2012 Tacoma is for the engine coolant... this has been normal for all brands for many years. This reading is somewhat important to cooling the transmission because the transmission fluid cooler is probably in the radiator; however, the engine coolant temperature doesn't tell you anything about the transmission fluid temperature.
I would have been very surprised if a Tacoma had a transmission
fluid temperature gauge at all - with or without numbers. My motorhome - built on a Ford F53 chassis and so using a Ford SuperDuty instrument cluster - has both engine oil temperature and transmission fluid temperature gauges (both without numbers) but I've never seen a light-duty vehicle with a transmission temperature gauge.
I agree that the dash gauges are just to indicate if operation is outside of normal range, or moving that way. As other have mentioned, an OBD instrument (such as a ScanGauge) is the modern way to go for more precise information.