Speedometer does not work

Is it related to my transmission which was recently rebuilt?

Welcome to 2CarPros.

If it worked prior to the repair, I going to say there is a good chance it is. There is a vehicle speed sensor on the transmission that could have been damaged, left loose, disconnected, or the wiring may have accidentally been damaged.

I attached a picture of the transmission. Going to each front wheel is an axle. Near where the axle attaches to the transmission, you will see a sensor. Make sure the wire is attached and tight. It should be on the driver's side of the vehicle.

Let me know what you find.

Joe