Let me start by admitting, this isn't my bonneville, but its a Series II 3800 in a Regal, so I hope you can still help me. Last night (300 miles from home) cruise control stopped working, and all I had was 1st gear, speedo stuck at 75mph (how fast I had been driving for about 500 miles already). So I drive the next 5 miles down the shoulder at about 15mph and get to a truck stop, shut off the car, and look for anything that came unplugged. When I decided to restart the car, the speed went back to 0 and everything was back to normal. I bought a speed sensor, but I have not found it yet. I have two questions:

1.) Does it sound like the speed sensor went bad or was the cause of my problem?

2.) Where is it?

This is my girlfriends car, so even if it seems fixed now, I am going to replace whatever is wrong because I don't want her having the problem again.

Thanks for your help and pretending it was a bonneville

Tom

Speed sensor is located on the top of the transmission, take off the passenger wheel and inner wheel well guards and u should see it. Right about where the axle output it at the end of the casing. I'm not sure how it'* held in but it'* either 1 or 2 maybe 13mm bolts then it lifts out. This could definately be the cause of ur loss of cruise and shift, because both these rely on speed input from the VSS.

When my Speed Sensor went bad a couple of years ago, I was travelling on I-80. The speedo went from 65 to 20 to 85 then to ZERO in a matter of minutes. The car started shifiting in and out of OD. The Cruise was inoperative. I shifted out of OD so the transmission would stop getting a confused signal and continued to drive another 10 miles with the Speedo reading "0". Then the speedo came back to life a few miles from home. I replaced the VSS and the problem never came back.

Just got done replacing the VSS, so far so good. That thing was a MAJOR pain to replace. Maybe its just because it was a regal and not a bonneville, but they made it so that the area around the sensor was not big enough for my hand, let alone a wrench or ratchet. I have heard of the VSS going bad in all different ways, some worse than others.

This one had a silver sludge on the end of it, I guess that is what made it not read for a while. It kind of looked like the anti-seize compound you can put on bolts. The car only has 30k miles, so I don't know what it could be.

Thanks for the help, let me know if you know what the mystery sludge could be after so few miles (and driven by an 85 yr old lady for 98% of them).