Last fall, just before I put my 82 away for the winter, I started to have problems with my speedometer not working for the first mile or so upon leaving my house in the morning. It would suddenly start working and would initally peg itself at 85mph for a second then read normally for the rest of the 10 mile ride to work. In the afternoon it would work properly right from the get-go. I figured it had to do with the cooler tempratures during the night and the fact that I had not turned the heat on in the garage yet.
I took the car out of it's storage spot 2 weeks ago and started driving it again. The first week it acted like it did last fall every morning. I figured it was maybe some lube or a part that was in the "cup" side of the speedometer head that didn't like the cold and started looking around for a new/used speedometer. Last week it stopped working all together. I found a NOS speedometer on ebay and wwon it for $55. What a deal!!! This past Saturday afternoon I had some time so I pulled the dash apart and guess what? The speedometer worked just fine when I spun the speedo input shaft by hand after I disconnected the cable. I jacked the rear of the car up and ran the car up to speed and lo and behold, the speedo cable behind the cluster didn't turn. I disconnected the lower cable from the Cruise Control Transducer and I found the plastic tip was not attached to the inner cable. I checked the transducer drive input and it was VERY hard to turn. That is why it would work/not work. The transducer was partially siezing up when it was cold and then the heat of the engine would warm it up and then it would work. All the while the inner cable would "slip" inside the plastic tip until it generated enough heat to cause it to bond itself back onto the cable. I ordered a new lower cable & transducer on Sunday and will await their arrival this week. I will also put the NOS speedo head in too. No sence in letting it sit in my "spare parts cabinet" for the rest of it's life (or mine ).