speedometer not working

[chev-obsession]

So about a year ago I finally got my 65 running and driving. I swapped in a 700R4 and used a calculator online to find out which speedo gears I need for the trans. cant remember what gears they are but when I drove it, it was off by about 50 mph.

After about 30 miles of driving the speedometer finally quit working all of a sudden and hasn't moved since. So since the cable is new and it was reading 50 mph off, some thing tells me that's not the problem.

So my 3 questions are:

1) Since the calculator that I used was obviously wrong, what speedometer gears for the transmission do I need for the speed to be right?

2) what likely happened to the speedo in the gauge cluster

3) how do I remove the gauge cluster? I have tried taking it out before but I could not get the light switch out.

[1963c-10]

In my experience, the worm gear inside the speedo is normally the culprit. They are made of plastic and can still be purchased. Check on ebay under chevy speedometer worm gear and you will find a few sources.

If you can verify the cable is good, I'd take the speedometer out of you dash and inspect it 1st before buying any parts. They are pretty easy to take apart, just go slow and take your time. I've had a few of these break over the years as they are plastic and just get brittle over time.

The 64-66 may be a little different than the 60-63, but if you get a total length of the gear, you should be able to find a replacement.

[chev-obsession]

awesome!! thanks!