When I drove my car home from buying it... I noticed the speedometer didn't work(obviously) and the trip computer just read 0. I found a jag box in the trunk with transducer... I haven't had a chance to check it out but I'm thinking this is not the proper part for my car? Mine is an 88' but says 87' on door and the vin is 141000 something and from what I've read this style transducer wasn't used until 144000. Seems this style is quite pricey...

 

That is a speed sensor that is mounted on the differential rear cover, right hand side. ViIN144262 is the change over point.

Previously, the transducer was mounted on the transmission, where a cable drive would attach on earlier versions. Left side, near the rear. (I'm assuming you have a V12 with the GM 3 speed automatic.)

The earlier part number is DAC4569.

 

yep v12 and 3 speed. I haven't gotten a chance to get to the transducer yet... I'm doing the trans pan gasket next week and wonder if it's easier to get to the transducer with the pan off or if it doesn't matter?

 

It doesn't matter. It's fairly easy to get to.

 

ok cool, thanks

 

Is that the same setup in a 1996 4.0 4 speed auto?

My speedo and odometer and cruise control all stopped working one day this early spring.

Not sure how to test if its the part in the trunk or the part attached to the rear.

Any help would be appreciated..

 

I don't remember if the 1996 has a trip computer or not, but if it does it can help you diagnose which part is the problem.

Take the car on a stretch of road where you get it up to steady speed and set the trip computer to AVG SPEED and press RESET. If once it resets and it registers a speed more or less equal to what you were doing, it is the Speed Interface part in the trunk. If it registers zero, then it's the Speed pickup that attaches to the differential.

Hope that helps.

 

Mac,

My 1996 does not have a trip computer. Is there a way to test the speed sensor in the rear? Is that a hall effects type sensor or does it have a gear on it?

Thanks for your help.

Bob

 

It's a hall effect. There is a toothed wheel on the differential carrier and the sensor mounts on the differential back cover.