My 01 Diesel left me stranded once due to this. Back in the old days the rheostat portion of the sending unit used to be real wire wound around a phenolic material - nowadays its more like a printed circuit board. Oh, and by the way, my OE sending unit, just like my lift pump, is a CARTER part - CARTER is stamped right on the rheostat part of the sending unit. I've bought lots of aftermarket parts from Airtex, Standard ignition, etc. that turned out to be the OE manufacturer. You might be able to use an aftermarket part and find it's really a re-boxed OE part. AN example - I just replaced the master and slave cylinder in my 01 and the replacement parts are the exact same manufacturer as the OE one the factory installed. Replaced the neutral safety switch in my 6 speed with one sold by Airtex - get it out of the box, and stamped into the plastic part of the housing is 'POLLACK' - same as the OE one installed in 2000. So I'd check online, like at Rock Auto, and look at the pics, before shelling out big $$ for a dealer part.
