1978 Speedometer Needle Bounce

[Mike F.]

My speedometer needle was bouncing on the 1978. The car has cruise control so I removed the output cable from the transducer (top cable) and used white grease to lub the inter cable. Well, now it doesn't work at all. I've removed the cable once again and it is not broken, cleaned as much grease off the cable end and blowen out the the output location. The cruise still works fine. Your thoughts?

[Oliver B.]

Re: 1978 Speedometer Needle Bounce

As far as I know, grease is "not the best of ideas" in that area.......

[Mike F.]

Re: 1978 Speedometer Needle Bounce

Oliver,
I'm heading to the local auto parts store to get the correct lub. I read some similar problems that others have had and what they used to stop the bouncing. Thanks for the reply!

[Oliver B.]

Re: 1978 Speedometer Needle Bounce

Well, it didn't help much, I'm afraid.......

[Harmon C.]

Re: 1978 Speedometer Needle Bounce

The transducers are wearing out or the grease is getting stiff in your year Corvettes and when the friction gets too much the lower cable breaks. This condition will cause the needle to bounce before it breaks the lower cable. You can change the lower cable as I think it is now broken by the extra friction added by the greaseon the upper cable. The lower cable will have a short life and will break again if you don't replace the transducer.

[Tom R.]

Re: 1978 Speedometer Needle Bounce

So you now have a compound problem...the transducer and lower cable. I replaced (rebuilt) my transducer years ago but when I removed it and took it apart (watch the spring), it was so rusty, the rust had turned to powder. They dry out after three decades.

[Mike F.]

Re: 1978 Speedometer Needle Bounce

Needle bounce fixed. The lower cable and transducer was replaced. The transmission cable nylon piece that goes into the input slot on the transducer broke off in the slot, and the output nylon slot was rounded so much that the speedometer cable didn't turn. I beleive that all this happened because the rivits that hold the bracket for the transducer were loose causing movement. They also have been replaced. Thanks for all the reply's and I'm going out for a test drive!

Mike Fotiades 11365
1978 SA Top Flight