: Bad Wheel Bearing? Cause speedometer problem?

05-02-11, 04:06 PM
Since I started rebuilding my free Deville it's had a noise while turning left, but not all the time. I took it in to the shop for them to diagnose. I thought CV Joint since it didnt happen all the time and was only during turns.

They called and said it is my left front wheel bearing.

Recently (one day only when wet) my ABS/TCS went nuts on the car and literally stopped my dead in my tracks. It kept doing this, and seem to do it when trying to drive the car straight and slightly left. I got out and pulled the ABS fuse and now it drives fine, no more crazy ABS/TCS engaging.

Also one day after the car sat for 4 days at the airport my speedometer would not work properly.

Are the two related all to a going out front wheel bearing on the left side? I thought these all in one unit hubs had a sensor in them that also reported back to the speedometer control? Someone else said that the speed is measured in the transmission. HUH??? I have not had a chance to read over the FSM yet. But I will replace the wheel bearing ASAP.

Thanks for clearing it up! :helpless:

johnny kannapo
05-02-11, 11:44 PM
Nope. The VSS sensor controls that. Its easy to service from underneath. It is held in with one 10mm bolt.
Check the connections. This sensor should send a code. Check for codes. It makes things easier.

The wheel sensors work in sync with the TC/ABS system & they sense wheel speed differences
between the 4 wheels to command the ABS to modulate the braking as needed. There is much more going on than just that.
The the wheel sensor sends a false wheel spin or lock-up signal it will apply ABS to that wheel to prevent it.


05-03-11, 11:39 AM
Awesome, thanks for your explanation, Johnny! I will check the VSS sensor you have pictured next time I'm under the car. I gotta get to ordering the hub now!

Is that picture you posted of the entire transmission unit removed from the motor/engine? I am assuming it is because it looks like the Transmission fluid cap in the lower right of the photo.