79’ TA — speedometer stopped working

[jvmagic]

Hi,

I have a 79’ TA and the speedometer started to make a bird chirping noises  a few months back until  the speedometer stopped working.

I did the speedo cable test by disconnecting from the tranny, drill in the reverse position, and the speedometer did work.  I reconnected the cable and then went to test the transducer (not sure I did this right).  I disconnected the smaller cable from the transducer and connected to the drill and the speedometer did not move. I’m not sure what that means so I’m hoping for some guidance. 

How can I confirm it’s a cable or the transducer.  Just want to figure out what to replace without pulling my hair. 

79’ Trans Am
403 motor
350 tranny
Cruise control


Thanks in advance

[FormTA]

I may be wrong here but if you disconnected the cable at the trans and spun it with a drill and the speedo worked then everything is good up to there. Sounds like the gear in the trans has stripped.

[b_hill_86]

I’d say, if you disconnected from the trans, and Speedo worked, it’d agree that the drive or drive. Gear in the speedo could be the culprit. The driven gear can be removed from the trans where the cable attaches. Should be able to inspect that gear or the drive gear inside the trans for wear.