High Oil Temp, Sensor Issue?

I put a new temp sensor on my oil pan and the gauge seems to be reading higher than the actual oil temp

Today I went and drove some hills. The gauge got up to 240 but checking the oil cooler, pan, and filter with an infrared thermometer showed nothing over 205. (I know it's going to be a little lower reading the outside of the pan or oil cooler but not that much). Water temp is around 150

'89 Peterbilt 379, Newly rebuilt 444xt, replaced the oil cooler core this morning, oil thermostat was replaced during the rebuild

Gauge looks to be original to the truck. Sensor is a cross reference match to the original Peterbilt part number

 

All the sensors got replaced when I rebuilt it. There's only one wire going to it, that got replaced a couple years ago when I completely rewired the engine

I have the old one in a box somewhere, looking back on it I think it was probably reading high too. It would get up to 240 without much effort. The new sensor is from PAI. The original Peterbilt part was 17-01685, that got changed to 140401. Cross that to a PAI 730394

I suppose I could switch the engine oil temp gauge with the trans or rear axle gauges to see if it's the gauge itself. I was just thinking maybe the new sensor and old gauge were not completely compatible, like the sensor was working on a different scale than the gauge