I have a 2001 Mercury Marquette. I took it to the Mercury dealer where I bought the car for a general check up. The mechanic said my front wheel ball bearings needed to be replaced. I just passed 39K miles. I asked him what would happen if I did nothing. He said my front tire might come off. I asked him the price and was overwhelmed. ($1200) I have noticed no problem driving the car but am very nervous until I know more. What do you advise?

Slow speed activation?
Have a good general service mechanic check your front wheel bearings for excessive play. Most reputable garages have the necessary diagnostic hardware to check most vehicle systems.
There may also be stored active or pending ABS codes that can guide a tech to a probable solution.

First check the air pressure in both front tires; if they don't match, that can cause the problem. If they do match take it back to the dealer that fixed it and take them for a drive with them driving it. Once they see the problem, tell them to fix it.

Depends where you go get it done the dealer will be most expensive and a tranny shop will be close to dealer prices you can find a good one at a junkyard and with proper tools if your mechanicly inclined would be the cheapes but its alot of work

IT COULD BE THE FRONT WHEEL BEARING, THEY USUALLY GO BAD BECAUSE ALL THE WEIGHT ON THE FRONT OF THE CAR

CHECK LOOSE DRIVE SHAFT BOLTS.WORN UNIVERASAL JOINT BEARINGS.

I had the same problem. It was the front sway bar bushings. I took it to the dealer when it was still under warrantee. The replaced everything from struts to the steering linkage. And it still made the annoying knocking noise. I was changing the oil one day and while I was under the car I started looking where the noise was coming from. I grabbed the sway bar and pulled on it. It was loose. I bought bushings for about $12 and that fixed it.
Hope this helps

Before you do this you might want to try fresh gear lube. On Ford products they use a synthetic additive in the rear and not in the front 4x4 axle.
The next thing would be to determine if it is a wheel bearing or a pinion bearing. You have to pull the axles and eliminate them as the problem. You might get lucky and not need to do the pinion.
The technical part of shimming the pinion gears with replacing the pinion bearing is about the worst part of the job. You won't know about the gears until you see them. You will need extra shims on hand.
It is a moderate job for two people. If you have all the parts it can be done in a day.

CHECK THE LINK RODS

duse the howl go away when you trun a conner ?if it duse its a wheel bearn. as for the squeak its hard to pin point. try finding some one how duse mud run they would be ableto help you with the howl noise. have a nice day

have u looked under the steering wheel or under the hood if u have call a ford dealer and ask them