This summer after winter storage the transmission temp gauge is dead. We have the Allison MTB 648. Anyone been down this road?
Have you checked the sender unit wire which should be in the elbow coming out of the transmission to the cooler? Is it the guage or the sender? You can check the guage in the dash by finding if it is getting 12 volts to it and then using a test light going to the s terminal and the guage should give you a reading.