Thread: Car wont shift, speedo stays at 0mph

So my car was running great, no issues at all. I decided to do a few pms this weekend so i replaced both vc gaskets, spark plugs and wires, and changed the oil. Did a few other things like changed the pulley and speakers. Anyways, the car started out by just staying in 1st and the speedo just stays at 0mph. I floored it for a second from a slight roll which then got the speedo to jump to 30ish and when i let off it went back to 0. Its started shifting but its very harsh... Anyone have this issue? Where should i start looking to fix this

The wires for the speed sensor drop down to the trans somewhere on that back corner of the motor where the alternator is. Did you by any chance tug or jerk that harness maybe dislodging a prong out of the plug? I forgot to plug up mine once and drove the car a couple blocks. My speedo didn't work and it SLAMMED into gears. Thought it was going to fall out of the car.

Yeah. It runs. But now that it started shifting everything is screwy since the speedo and hud stays at 0mph. The shifts are really firm

Originally Posted by dbextreme

The wires for the speed sensor drop down to the trans somewhere on that back corner of the motor where the alternator is. Did you by any chance tug or jerk that harness maybe dislodging a prong out of the plug? I forgot to plug up mine once and drove the car a couple blocks. My speedo didn't work and it SLAMMED into gears. Thought it was going to fall out of the car.

Any pics or how many pins the connector is?

That was it!!! Found it and found a wire pulled from the connector. Shifts great! Thanks man, i owe you a beer or 2

I'll have to crawl under mine to get pics.. lol I believe it's a two pin connector and the sensor I believe pops into the diff cover under the ps pump.

Sensor #10.

Where is the speed sensor located on a 1999 Pontiac Grand Prix - JustAnswer

Awesome!! Glad I could help!!!