Topic: Leaking from Transmission
in Forum: C3 Driveline Components
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Lemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
It looks as if I have a fluid leak fro the speedometer connector. Is there a gasket or something behind the knurled nut?
What do you recommend if I cannot get it tight enough by hand to stop the leak.
And is there an easy what to get to that knurled nut?
What do you recommend if I cannot get it tight enough by hand to stop the leak.
And is there an easy what to get to that knurled nut?
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There is a little bolt and a holddown clamp that holds the speedo drive gear in the tranny,its a bullet shaped gizmo and slides out the side of the tranny,and it has an O-Ring on it,once you pull it out you can get to the knurled nut much easier,the fluid is prolly leaking past the O-Ring
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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IF the thing is leaking where the knurled nut goes on, the internal seal is leaking. You might get lucky and just replace the seal, but chances are....the gear itself is worn, and has a groove in it from the seal.
To check, remove the bullet as Ron described, and pull the gear out of the bullet. Look at the end that the speedo cable goes into. About 1/4" or so from the end, you may find a groove cut into the gear, straight around the gear. There is a normal groove in the gear, but it is like screw threads that starts at the large end, and runs to the cable end...that is for lubrication purposes.
The actual seal for the gear is either held in with a very small wire circlip, or, if the bullet is steel, the seal will be a metal clad seal, similar to the rear seal of the trans, only LOTS smaller in diameter. An aluminuminum bullet will have a soft rubber seal that can be chaged easily by removing the circlip, popping the seal out, inserting the new seal, and re-installing the little circlip.
If you have a steel bullet, it's easier to just replace it than it is to find the inner seal, and replace it in your old bullet. The steel bullets, with seal already installed are only aboot $3-$4.
As Ron says, there is also the o-ring around the outside of the bullet. Never hurts to replace that little bugger, too.
There is NO seal or gasket on the nut of the cable.

To check, remove the bullet as Ron described, and pull the gear out of the bullet. Look at the end that the speedo cable goes into. About 1/4" or so from the end, you may find a groove cut into the gear, straight around the gear. There is a normal groove in the gear, but it is like screw threads that starts at the large end, and runs to the cable end...that is for lubrication purposes.
The actual seal for the gear is either held in with a very small wire circlip, or, if the bullet is steel, the seal will be a metal clad seal, similar to the rear seal of the trans, only LOTS smaller in diameter. An aluminuminum bullet will have a soft rubber seal that can be chaged easily by removing the circlip, popping the seal out, inserting the new seal, and re-installing the little circlip.
If you have a steel bullet, it's easier to just replace it than it is to find the inner seal, and replace it in your old bullet. The steel bullets, with seal already installed are only aboot $3-$4.
As Ron says, there is also the o-ring around the outside of the bullet. Never hurts to replace that little bugger, too.

There is NO seal or gasket on the nut of the cable.
Joel Adams
C3VR Lifetime Member #56
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in Forum: C3 Driveline Components
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