SPEEDOMETER SENSOR

I just bought a used 2004 chevy tahoe z71. I drove off the lot and made a stop to get something. After I got back in my truck and started it up I noticed that the speedometer gauge was on 80 but I was parked. As I drove off it increased like it should but it was registering way to high. As I got up to highway speed and got home it was buried at 120. I already called the salesperson but I can't get it back in until monday. Can you please tell me what is wrong so I know what to expect before I get there monday?

Thanks for the reply. How long does that take?

Thanks for the advice and knowledge. I took it in today and thats exactly what they said, it needs a new cluster assembly. I appreciate the knowing what to expect going in. Thanks again.

2002 chevrolet tahoe 95000 miles v8. Speedometer stuck on 110. Does the cable need replaced or what is the problem?

You will need to replace the instrument cluster. I am seeing this is a fairly common problem. You will need to purchase this from a GM dealer, they will have to reprogram the new part with the appropriate mileage and engine hours.

I just purchased this vehicle and noticed the speedometer sticks when on the highway, but one you turn the truck on/off it goes back to normal. Have you had any other issues of knowing that the 2004 Chevys have this problem?

Hello I own a 2003 Chevy Tahoe and there was a recall and class action suit on this problem- It includes the enire panel. If your truck has under 70000 you can get it replaced free at a Chevy dealer.
Rachel