The type of thread Scotty is referring to is called National Pipe thread and it is tapered as he stated. The sending units usually leak at the connector. I had one actually blow the connector out of the socket and it caused my oil light to come on. I actually had to pull over on the side of the road because I was afraid that something catastrophic had happened. The sender isn't as easy to access with the wheel on (at least on the Park Ave). I wasn't able to find a replacement and ended up using a 1/4" NPT plug with Teflon tapeuntil one came in. So if you crack the hosing on the new sender you can use a plug if you have to.
Remember: When adding Teflon tape to a fitting wrap in the clockwise direction so it doesn't unravel on you when you try install the fitting.
Jeff
