Car problem with video

Hi guys,

Few weeks back I posted about a transmission problem. 1996 Cutlass Ciera. Well I got the transmission repaired, used. Got the car back tonight. Now I have a new problem. I get the car to highway speed and the needle drops, from 55 down, wildly. Sometimes it lurches, sometimes its momentary. I included video so you can se what it does. It’s clearest at the end, round the 1:15 mark. Any clues? Forgot the URL

There may be a speed sensor problem causing the trouble.

Given the situation, it’s probably a problem related to the transmission installation. Maybe a poor contact with the electronics at the transmission. I’d call the guy who did the transmission repair. If he sighs and asks you to bring the car in, you’ve probably found the problem.

But it could be coincidence. Speedometers do fail sometimes, and the description you give is exactly what happened with the last two of mine that failed.