Received the new speedo pinion in the mail (see below) and then went immediately into the installation process.
The new pinion was an original that sat in someone's garage for awhile. We found it on ebay for $25, $30 with shipping. Out of the box it looked brand new and slipped right into the housing. Moss had also shipped our new speedo cable, so installation was the next step.
Step 1: Install the Pinion.
The pinion and housing screwed smoothly into the bottom of the transmission (see below). This was much less drama filled than I expected. With plastic threads and the huge wrench it takes I was sure something would split, crack or strip. None of the above occurred however.
Step 2: Install the Speedo Cable/Speedo
Again, for some strange reason everything went together quite easily. After a few months of working on the Sprite this was considered quite an anomaly. We laid the cable into the engine bay and then routed it to the pinion. The cable screwed on with little effort. From the bottom of the car I fixed the cable into the metal tab along the left side of the engine bay and then through the firewall. We purchased a new firewall grommet and that went in easily as well.
Before connecting the cable to the speedo we put the transmission in gear and rotated the rear wheels. The idea was to see the speedo cable end turn before connecting it the the speedo and putting the speedo in the dash. It worked.
Pinion and cable test complete, we connected the cable to the back of the speedo and re-installed the speedo into the dash. This was probably the most difficult part of the process. Our speedo has a funny little bracket that holds it from 1 side. Getting the small nut and washer on it took a few minutes.
Step 3: Refill the Transmission with Fluid
In order to remove the pinion the transmission has to be drained because the pinion is at the bottom of the transmission. Learning the lesson from the our first attempt at this, we utilized the old fuel pump to refill the transmission. In addition, when we drained our transmission fluid we drained it into a container that allowed us to measure it. So when we went to refill, we provided the pump the same amount of oil. This allowed us to setup our pump rig and move onto other projects.
Step 4: Test the Speedo
We had the wheel off the ground for the under the car work we were doing, so once the transmission fluid was back in we started Tracy up and gently put her in gear. The speedo registered immediately and move smoothly up and down with acceleration/deceleration.
This concluded the speedo repairs and we moved on to more projects.
New pinion in original box
Pinion, housing and cable installed on transmission