Speedometer problems 1977
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
Speedometer problems 1977
Hi i just started having speedometer problems with my 1977.
It has TH350 i thought it was the driven gear but it looks fine, the drive gear is green 7 tooth and it looks fine also.
I put a cordless drill on the tranny cable end and the speedometer does work.
I was going to order both gears but have run into a snag, the driven gear off of the cable is a red 21 tooth and from what i can see that gear is for a 4 speed standard and that seems odd to me, any ideas ?
Thanks
It has TH350 i thought it was the driven gear but it looks fine, the drive gear is green 7 tooth and it looks fine also.
I put a cordless drill on the tranny cable end and the speedometer does work.
I was going to order both gears but have run into a snag, the driven gear off of the cable is a red 21 tooth and from what i can see that gear is for a 4 speed standard and that seems odd to me, any ideas ?
Thanks
Last edited by clight77; Jun 17, 2007 at 04:55 PM. Reason: correction
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
The speedometer in my 1977 vette TH350 is still jumping around last summer i replaced the cables and gears but it did not help.
I heard some where there is a clip that locks the drive gear or worm gear in the tranny tailshaft from slipping.
Does anyone know what that would be called or where to find it ?
I think the worm gear on the tailshaft of the tranny is slipping..
Thank you
I heard some where there is a clip that locks the drive gear or worm gear in the tranny tailshaft from slipping.
Does anyone know what that would be called or where to find it ?
I think the worm gear on the tailshaft of the tranny is slipping..
Thank you
Melting Slicks
Joined: Feb 2002
Posts: 2,625
Likes: 0
From: Cut n Shoot TX
The speedometer in my 1977 vette TH350 is still jumping around last summer i replaced the cables and gears but it did not help.
I heard some where there is a clip that locks the drive gear or worm gear in the tranny tailshaft from slipping.
Does anyone know what that would be called or where to find it ?
I think the worm gear on the tailshaft of the tranny is slipping..
Thank you
I heard some where there is a clip that locks the drive gear or worm gear in the tranny tailshaft from slipping.
Does anyone know what that would be called or where to find it ?
I think the worm gear on the tailshaft of the tranny is slipping..
Thank you
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
If you have cruise, it's probably the cruise control transducer. Disconnect at the transducer & spin the cable to speedo.
Bypass the transducer: Possible a 86-88 MC SS lower cable may connect & screw to the upper cable.
Bypass the transducer: Possible a 86-88 MC SS lower cable may connect & screw to the upper cable.
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
Maybe i am over looking something
I ran a cordless driver to the cable where it connects to the tranny and no bounce,so it must be running through the transducer from there ? Right ?
Thanks and be patient . LOL
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Race Director
Joined: Apr 1999
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From: CORVETTE 77 385 C.I. TEXAS
"The speedometer in my 1977 vette TH350 is still jumping around last summer i replaced the cables and gears but it did not help."
Yes, if driving the cable from the trans., then it goes through the transducer (W/ cruise) to speedo. Most likely the jumping is from the transducer.
Yes, if driving the cable from the trans., then it goes through the transducer (W/ cruise) to speedo. Most likely the jumping is from the transducer.
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
"The speedometer in my 1977 vette TH350 is still jumping around last summer i replaced the cables and gears but it did not help."
Yes, if driving the cable from the trans., then it goes through the transducer (W/ cruise) to speedo. Most likely the jumping is from the transducer.
Yes, if driving the cable from the trans., then it goes through the transducer (W/ cruise) to speedo. Most likely the jumping is from the transducer.
Thanks
Thread Starter
Heel & Toe
Joined: Aug 2006
Posts: 15
Likes: 0
Hi have not logged in for a couple of years,have not driven my 77 vette in as many years.
I have a question? Can cruise control work with the transmission part of the cable removed,as mine does,just bought a transducer and speedo still does not work,bought new cable and driven gear previously.
I jacked the car up and put it in gear and cable from tranny does not spin,so i gather it is the drive gear in tranny now.
But how can cruise control work if this is the case?
Thanks
I have a question? Can cruise control work with the transmission part of the cable removed,as mine does,just bought a transducer and speedo still does not work,bought new cable and driven gear previously.
I jacked the car up and put it in gear and cable from tranny does not spin,so i gather it is the drive gear in tranny now.
But how can cruise control work if this is the case?
Thanks
