My truck (1990 with a 727) came without anything at all attached to the transmission where the speed sensor is supposed to go... I assumed it actually needed a cable til I found out that it's electronic. The plug for the sensor is still hanging down there, but like I said there's nothing on the outside of the transmission. I got the impression from searching here that I need more than just the sensor that you can get at NAPA. Is that correct, and if so what else do I need?

I also need some recommendations for aftermarket gauges. I need a trans temp gauge, tach, and pyrometer at least. Sounds like people have had problems with certain brands but I couldn't get a clear picture of who's got the best ones. I don't care what they look like, I just need them to be accurate!

 

For your speedometer you should need a vehicle speed sensor (VSS), you should also need some kind of a gear box between it and the vss to make the speedo read correctly. The gear box I know you can get at a speedometer shop if you can find one, they can custom make them to any ratio.
As for the gauges, I'm happy with my autometers, but I have of a lot of people who are not. If I were buying gauges again I would get these, https://www.sourceautomotive.biz/ind...id=61&Itemid=1

 

Only the 4x4's used the reducer box. The D's came straight off the transmission.