Digital Transmission Temp Gauge Kit, 300F 2-1/16 in

A 2-1/16 inch (52mm) digital transmission temperature gauge that reads automatic transmission fluid from 68 to 302 degrees Fahrenheit. The kit is complete: gauge with aluminum housing, black face and tinted lens, a 1/8-27 NPT electronic temperature sensor, a 2 foot power and sensor harness, a gauge visor, a mounting bracket with hardware, and printed installation instructions. The LED display has 10 selectable solid colors plus 2 color-cycle modes, and it self-calibrates every time you power it up.

Heat is what kills an automatic. ATF that lives around 175 degrees will go a long time; the same fluid held in the 240 to 260 range oxidizes fast, varnishes the valve body, and cooks the clutch friction material off the steels. On a towing rig the converter is the heat source, so by the time a slipping torque converter clutch or a loaded 4L60E, 4L80E, 47RE or 5R110W shows a shift complaint, the fluid has usually already been abused. A gauge in the dash tells you that hours before the transmission does.

The 1/8-27 NPT sensor threads into a test port on the case, or into a T-fitting spliced in the cooler line. Put it on the hot line - the line leaving the transmission on its way to the cooler - not the return, or you will be reading the temperature of fluid that has already been cooled and every number will look fine. A pan-mounted sensor reads sump temperature, which runs lower and lags, so it is the more conservative place to put it. Run the harness through an existing grommet in the firewall, feed switched 12V from an ignition-on source so the gauge does not sit awake with the key off, and ground the gauge to bare chassis metal rather than a painted bracket.

Fits any car or truck with an automatic transmission - the mounting is universal (pillar pod, dash pod, or the included bracket) and the sensor only needs a 1/8-27 NPT port or a cooler-line tee. Backed by a one-year limited warranty from the manufacturer.