74 dart speedometer issues

The ticking could be the cable turning, but the cable might not be plugged into the back of the speedo.
Chk that first.
If it's all hooked up, then start at the trans and make sure everything is turning when the wheels do.
Speedo gear turning, cable turning in the housing, and so on.
You'll find it, and it may actually be the speedo head in the end.

I saw one on here today for sale at a good price.