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81 speedo transducer

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Old 07-11-2019, 09:00 AM
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Danny Halperin
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Default 81 speedo transducer

Hi everyone I have an 81 it has a transducer so the speedo cable from the speedo attaches to the transducer which is located below the master cylinder the funny thing is I don't have cruise control so do I take that thing out and buy a new speedo cable. Goes directly to the transmission question question anybody no thank you very much
Old 07-11-2019, 02:07 PM
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7T1vette
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I am 'reading between the lines' on this one, but I suspect the car DID come from the factory with cruise control. I also suspect that the control stalk on the steering column had some problem and a PO decided to install a non-CC stalk, as the correct stalk was not available at that time or the cost was deemed 'prohibitive'. If you have an AIM for that model year, compare the installation of the tranducer (location, hardware, wiring) to the AIM depiction. If it is the same, it's most likely factory installed. And, if that's the case, you should be able to get the cruise system operational by replacing with the proper switch stalk AND by problem solving any "issues" with the transducer or CC system.
Old 07-11-2019, 02:17 PM
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Danny Halperin
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Think I'll just take the transducer out I don't need it I don't need cruise control there isn't a cruise control stick on the column anyway it's easier just to put a new speedo cable from the speedo to the transmission 64 in thanks for your offer of advice appreciated
Old 07-12-2019, 04:47 PM
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7T1vette
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I will only add that the cruise feature is really nice, if going on a longer trip with the limited leg room in a C3.
Old 07-12-2019, 05:26 PM
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L-46man
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Danny. The CRUISE CONTROL transducer is what you're talking about.

In a nutshell, you can bypass it for speedometer operation.
You must be careful in the LENGTH of the cable...insofar as you don't want any kinks and must maintain a generous curvature.

The CCT is a V -drive.....the cable comes in and goes out the same way.

Be aware there is ANOTHER speedo cable in the car...the short one.

Now you can wire the cruise control stalk to the ejector seat! LOL

Good luck.

Unkahal
Old 07-14-2019, 11:30 AM
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Danny Halperin
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Default thanx

Wierd i dont have cc controls on column


so ill disconnect transducer


dont need it




Originally Posted by l-46man
danny. The cruise control transducer is what you're talking about.

In a nutshell, you can bypass it for speedometer operation.
You must be careful in the length of the cable...insofar as you don't want any kinks and must maintain a generous curvature.

The cct is a v -drive.....the cable comes in and goes out the same way.
Thanx!


Be aware there is another speedo cable in the car...the short one.

Now you can wire the cruise control stalk to the ejector seat! Lol

good luck.

Unkahal
Old 07-14-2019, 03:39 PM
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HeadsU.P.
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I wonder if what you are referring to is actually a "reducer" and not a transducer. A reducer has a 90* connection for input / output speedo cables There are gears inside that reduce one side of the unit. They are commonly sold by speedometer companies. They are popular and easy way to recalibrate the speedo in the event the rear axle ratio was changed. People would just install a reducer instead of changing the trannys output shaft gear, known as the drive gear.
Old 07-14-2019, 10:55 PM
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Danny Halperin
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thanks
I think it's a transducer it's got an input for the cable from the Speedo cable and then it's got two wires female connector and a ground wire
i just disconnected it.
going to put new speedo cable from speedo to tranny bypassing the transducer or reducer??


Originally Posted by HeadsU.P.
I wonder if what you are referring to is actually a "reducer" and not a transducer. A reducer has a 90* connection for input / output speedo cables There are gears inside that reduce one side of the unit. They are commonly sold by speedometer companies. They are popular and easy way to recalibrate the speedo in the event the rear axle ratio was changed. People would just install a reducer instead of changing the trannys output shaft gear, known as the drive gear.
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Old 07-16-2019, 04:44 PM
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SwampeastMike
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That's DEFINITELY the cruise control transducer. You'll probably see a bracket behind the throttle linkage that used to hold the vacuum servo. If for some reason the servo is still there you can sell it for a good price as they haven't been available new for years.
Old 07-16-2019, 04:59 PM
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Danny Halperin
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hey swampman Mike.
thanx.
im surprised theres a transducer.
this 81 i have has no cc on steering column.
you saying i can sell the transducer?
looks hard to get out litte room to work.
just bought new speedo cable to go direct from speedo to tranny. 64".
gotta take old short one out🙄 take panel out
and gotta check headlight switch too
headlights work but not opening.
might have vacuum leak or overide switch might be on. where that ***** is not sure hope its near HL switch so i can check.



Originally Posted by SwampeastMike
That's DEFINITELY the cruise control transducer. You'll probably see a bracket behind the throttle linkage that used to hold the vacuum servo. If for some reason the servo is still there you can sell it for a good price as they haven't been available new for years.
Old 07-16-2019, 05:13 PM
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SwampeastMike
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Not the transducer--they're easy to find. It's the vacuum servo that's very hard to find. It's mounted to the intake manifold (via a bracket) directly behind the throttle connection at the carburetor.

The cruise control system is vacuum operated. If it wasn't disabled properly you'll have a HUGE manifold vacuum leak. Did you recently monkey with any "unknown" vacuum lines around the brake pedal?
Old 07-16-2019, 10:31 PM
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Danny Halperin
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ok. vacuum servo. thanx.
not sure ill check. new to this.
didnt mess with brake area vacuum hoses.
but been trying to figure out why headlights wont pop up. also engine is little rough when starting but idles nice when warmed up. that indicates i think vacuum leak? mabey headlight switch?
thanx


Originally Posted by SwampeastMike
Not the transducer--they're easy to find. It's the vacuum servo that's very hard to find. It's mounted to the intake manifold (via a bracket) directly behind the throttle connection at the carburetor.

The cruise control system is vacuum operated. If it wasn't disabled properly you'll have a HUGE manifold vacuum leak. Did you recently monkey with any "unknown" vacuum lines around the brake pedal?
Old 07-16-2019, 11:08 PM
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Danny Halperin
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hey Mike
i think i got one. how would i plug up the vacuum line if i dismantle it?



Originally Posted by SwampeastMike
Not the transducer--they're easy to find. It's the vacuum servo that's very hard to find. It's mounted to the intake manifold (via a bracket) directly behind the throttle connection at the carburetor.

The cruise control system is vacuum operated. If it wasn't disabled properly you'll have a HUGE manifold vacuum leak. Did you recently monkey with any "unknown" vacuum lines around the brake pedal?

t
Old 07-19-2019, 05:37 PM
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SwampeastMike
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Yes, that's the cruise servo.

Things in there look quite original.

The cruise system connects to vacuum via a fitting screwed into the intake manifold just behind the carburetor. If you have an automatic it has three branches with the metal line connected to the top leading to the transmission modulating valve. Two if you have a standard. I'm not sure which side of the fitting the cruise attaches to but it is NOT the one that leads to a strange little tee beside the brake booster that has two medium sized connections and one tiny connection (this feeds the HVAC and headlamp doors). Cap or plug the other side connector and the cruise vacuum is completely disabled.

If you have zero desire for the cruise system to work you'll get a nice price for the servo.

Are you positive the cruise switch isn't there? It's integrated with the turn signal lever with a button in the very end and a slide switch in the stalk. The switch labels may be worn away.

Last edited by SwampeastMike; 07-19-2019 at 05:37 PM.

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