Hi Tony
I just pulled out the speed sensor and dash cluster. The speed sensor on our Aussie spec Corolla AE112 , however, is a pure mechanical part that connects directly to the dash with no electric parts at all. I found out the reason for my speedo stop working is that speedo cable jumped out of the socket on dash cluster. I put it back in and took it for a drive, however as soon as speed pick up to 50km/h the speedo is busted and jumping up and down and shaking again.
I also checked speed sensor ,there is no teeth missing, just a little bit stripped on the edge ,as its a 20 years old plastic gear .