Yes, I only have the old gauge. And calling SW is just an exercise in frustration. they know NOTHING! First call the tech says they only used 1 sender for all their fuel gauges. That's odd I replied. I see 3 differing part numbers with 3 differing ohm readings on the website! SILENCE! The next call to SW the tech was blabbering nonsense.. remember that old saying "if you can't dazzle'em with brilliance, baffle'em with bullshit!" that was him and he wouldn't stop talking! I hung up. the rheostat idea is a good one but I haven't got or found a unit to test with. Mike P offers some possible solutions. I have the gauge number but SW doesn't know what sender goes with it.. or so they say. I think I could send it to Dakota Digital or the like and they can test it but the shipping could kill that idea. Can I say how much I miss Radio Shack!