Dan,
You should have looked up what the sensor was before you bought a replacement. I believe that the engine is a Cummins and there is a very good chance that someone at a Cummins shop could either tell you what it should be or even sell you a correct part.
Baring that, you need to do an experiment with you current instruments powered up and a couple of alligator clips and about a 300? wire wound pot. You can use that to determine what is low and what is full scale. Then, if you can't actually find a match (very unlikely) you can do weirdness with little resistors to make what you can get be what you want. (I have to do this sometimes for strange foreign boat engines that come my way.)
All the senders come in all kinds of ways. I won't even go into how many there are, just suffice it to say a few. The calibration and working range also vary all over the place.
Matt
