SENSOR, TEMPERATURE, 1/8NPTF MALE, SHALLOW DEPTH, SHORT SWEEP ELEC.

Thank you for your question. #2259 has a 1/8"NPT male thread on it. If your '03 F550 has an 1/8"NPT thread fitting on the transmission test port, you could certainly use this sensor. If not, you would need to get an adapter fitting to match your thread.

I believe it will, but the sender you are looking at is a shallow depth type: mostly used for in the transmission pan bang to operate. If you do go with this sender in a pan bung, I recommend making a grounding strap for this sender with a 1/4" hose clamp, some solder, and a long ground wire to ground the sensor. The bung and or the npt adapter does not ground this sensor very well.

Thank you so much for contacting us. You DEFINITELY do not want to use teflon tape. It will impede the sending unit's path to ground and cause the gauge to read low or not at all. The sending unit is brass and the thread is tapered. It should seal up perfectly without any leaks. If you're still concerned, you can use a tiny dab of liquid thread sealant. Hope this helps!

Thank you so much for contacting us. Not totally sure I follow you, but if the actual temperature is 175˚ the sensor should be showing around 230 ohms resistance to ground. A 335 ohm reading would suggest a temperature of around 155 - 160 or so. The higher the temp gets, the lower the resistance the sender outputs. If you're using teflon tape on your sender, it will increase resistance to ground and cause your gauge to read low or not at all. If the gauge lacks an adequate ground or is sharing a ground with the gauge lighting circuit, the gauge will likely read high. Finally, if you're attempting to use an infrared gun as a diagnostic tool for a temp gauge, you should anticipate it reading at least 10 - 15% lower than the gauge as it only measures surface temp, not internal fluid temp. Hope this helps!

Hi Rodney, thank you for contacting us. A general overall range is 1123 ohms (+/- 102) at 100 degrees F to 65 ohms (+/- 4) at 250 degrees F. If you need additional temperature points, hit the Chat link at the top of the page or you can email us here: http://www.autometer.com/resources/index/ask_a_question

Thank you so much for contacting us. While the 2258 and 2259 are identical in terms of function (only the length is different), the gauge is only capable of utilizing one sender. The measurement circuit is resistive and adding another leg to it would cause both senders to read erroneously. Sorry for the bad news.