I'm trying to find the VSS (vehicle speed sensor) on my trans with no luck. Far as I know it's the stock trans (350) with a built 350 motor, at least that is what I was told. Speedometer doesn't work and I have already replaced the speedo cable but no joy. In researching the issue I came across the VSS and I do have a sensor wire hanging below the car and it's all beat up but I can't find where it goes. Not even sure if it is the VSS sensor. Felt all around the transmission, where I can reach, and can not find an opening or extrusions for a sensor. Searched through the Chassis Service Manual but can't find anything in there either.

Please help!!

Thanks!!
-Mack

 

If everything is stock: Transmission and Instrument Cluster, then you don't have an electronic vehicle speed sensor. A gear in the transmission spins the speedo cable insert. The speedo cable insert spins a magnet in the speedometer and that magnetic field moves the needle. If the speedo doesn't work, its one of those things. There is a diagnosis chart in section 4B of the chassis manual.
The wire could be anything, transmission-related or not, but my first suspicion is the TCS (Transmission Controlled Spark) system.

 

There os no VSS on your car. That extra wire hanging it probably for the kick down switch for turbo 400 cars. It’s included on every harness. If your cable is good it probably a bad speedo head or possible broken gears in the tail of the tranny. I have a good working speedo for a floor shift car available if needed.

 

The "vehicle speed sensor" is a set of gears on the output shaft of the transmission. These gears drive a flex shaft cable that drives the speedometer.

 

Does the car have cruise control ? Kind of rare in those days but if it does it could be something in the cable going to or from the CC.

You can check the speedometer by cutting a short piece of your old cable and putting it into the back of the speedometer. Chuck it in a drill and spin it slowly counterclockwise and see if the needle moves.

 

I believe it's called the speedo (speedometer) driven drive gear Section 7 of CSM.

 

I see you're in Prescott. Get in touch with Jim Schultz in Chino Valley. He's the founder of the Oldsmobile Club of Arizona and should be able to help you figure this out.

His contact info is at the bottom of the AZ Olds Club home page:

https://www.azoldsclub.com/

 

Thanks everyone!!

I kind of thought that there was no VSS as it is a mechanical guage and I couldn't find any info on it. Didn't know about the magnet in the speedometer and I'll be testing that shortly with a piece of the old cable.

Again, thanks for the help!!
-Mack