Transmission oil temperature gauges read like round-dial thermometers and display temperature ranges from approximately -60 degrees Fahrenheit to 260 degrees Fahrenheit. Some are analog gauges, some have an LED display, and others are a combination of both.
When reading a transmission oil temperature gauge, the temperature ranges and their indications are of greatest significance. An average temperature range for a 2-liter engine that runs for a while and is free of stress is about 80 to 95 degrees Fahrenheit. High-performance engines or those recruited for towing vehicles or trailers typically have elevated transmission and oil temperatures.
Approximately 100 to 110 degrees Fahrenheit is the temperature range of an engine that is working hard. Side effects in this range include thinning oil, decreased engine lubrication and decreased internal heat from nearby parts.
While oil typically does not run cool, a transmission oil temperature gauge reading of 70 degrees Fahrenheit or below possibly indicates a faulty oil cooler. In cold weather, all engines may experience low oil temperature, even if there is no oil cooler installed or the water temperature gauge registers as normal.
The main difference between analog and LED transmission oil temperature gauges is their display. Some LED versions, such as AEM digital transmission temperature gauges, provide temperature readings in 1-degree F increments.