1978 Speedometer
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
Could be the head
Cruise control transducer(If you have one)
Drive gears
Cable/s
Just pick the easiest and start looking.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,847
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
If you have cruise, take the cable loose that runs to the speedo, attach a drill to the end and (in reverse) check to see if the speedo works. If it does then you have a failure either in the transducer, lower cable or the gear in the tranny. If it doesn't work then you probably need to pull the speedo and have it serviced.
If you don't have cruise, you can do the same test at the transmission but its not quite as easy.
Willcox
If you don't have cruise, you can do the same test at the transmission but its not quite as easy.
Willcox
Pro
Joined: Aug 2007
Posts: 707
Likes: 31
From: Pitman NJ
If you have cruise, take the cable loose that runs to the speedo, attach a drill to the end and (in reverse) check to see if the speedo works. If it does then you have a failure either in the transducer, lower cable or the gear in the tranny. If it doesn't work then you probably need to pull the speedo and have it serviced.
If you don't have cruise, you can do the same test at the transmission but its not quite as easy.
Willcox
If you don't have cruise, you can do the same test at the transmission but its not quite as easy.
Willcox
I have a 79, and the same thing happened. It was my lower cable. There is more tension on the lower cable (because of the transducer), so it will fail first.
My fix was to get on long cable, and by-pass the transducer.
Instructor
Joined: Sep 2010
Posts: 229
Likes: 1
From: Grants Pass Oregon
