Speedo
Thread Starter
Instructor
Joined: Jun 2010
Posts: 165
Likes: 0
From: concord ohio
Speedo
my speedometer on my '78 is not working, the speedo will turn once I disconnected the cable from the cruise and spun it with a drill. So, that leaves the lower cable or the trans gears. The car has a 3.08 rear and I need to know what color gear or how many teeth i need. It's a turbo 350. Is there anything I missed?
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Did you verify the cruise control transducer? 
My money's on that being bad. You could probably lift the rear wheels off the ground, put the car in neutral and spin the tires to verify that the lower cable is working (verify the end that goes into the transducer, have someone eyeball it while you spin the tires). If this works, it's the transducer.
My money's on that being bad. You could probably lift the rear wheels off the ground, put the car in neutral and spin the tires to verify that the lower cable is working (verify the end that goes into the transducer, have someone eyeball it while you spin the tires). If this works, it's the transducer.
Instructor
Joined: Jan 2012
Posts: 215
Likes: 6
From: Mebane, NC
The ends of the internal cables wear. Even though they turn, they may not be long enough to engage. I had the same problem after I had my dash apart. All the built up crud made it work before, after I cleaned it up,not because the cable was to short. New cable, all is good. I have a simple one cable, tranny to 4 speed. Cruise control complicates things.
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
Speedo's can be a pain. Here's the problem I had in my 79 L-82 with a TH350 auto transmission: The drive gear was worm down in the center of the teeth causing my speedo to be erratic. Over thirty years of wear I guess. Not that hard to change. Just a pain in the butt laying on your back under the car.
By the way, new 8 tooth drive gear smooth as can be.
By the way, new 8 tooth drive gear smooth as can be.
Last edited by thegazman; Jul 9, 2013 at 09:24 AM. Reason: addition
