Hello,

I have a 2004 X-type 3.0 Gas with Auto Trans. I bought it with 80,000 miles on it and it had a driveline noise. I thought was the well documented center drive shaft bearing. I replaced the drive shaft, which included a new bearing, and still have the noise. It certainly seems to me to be coming from the center rear of the car, my basic test was driving with driver window down and then passenger window down and the sound doesn't "seem" to be louder from either side. I am thinking it is coming from the rear differential, possibly an internal bearing. I haven't drained the fluid yet to see if low or other signs of issues.

The sound is more of a low rumble then a high whine. Which is why I think it is more of a bearing sound then a warn gear.

I still have the weights that are bolted on the diff and the hubs, so those aren't missing and causing.

I haven't seen any write-ups about differential issues on this forum. Is it good to assume this may be particular problem with my differential and a used differential from a wrecking yard may be a viable solution?

Is it still more likely to be a wheel bearing then differential issue?

Could it just be the diff mount?

Thanks,

Royce
Northern California

 

What speeds are you hearing this noise?

 

It is heard at most any speed. Seems to be loudest between 35 - 55. But never goes away.

 

Have you tried taking it somewhere to put on a hoist and spin it up to that speed to see where the noise is coming from? Otherwise you'll need 4 jack stands to do the same while at home. You can then use a stethoscope or a long screw driver to see where the noise is the loudest.

 

No I haven't tried that. I do have a cut down broom stick handle that I have used for the same purpose to find which engine pulley was making noise, for previous issue with different car. I don't have access to a hoist. I do have access to jack stands. I am concerned running it with the tires off the ground could cause the wheel speed sensors to trigger a fault and set off the check engine light if the diff is open, example left side spins much faster than right side (or vis-a-versa). I don't want to have to take it someone expensive to reset. Anyone know if that will happen? If yes, would it reset on its own over time (my Ford will reset after three starts if the same issue is not re-occurring) or is there an easy process to reset?

 

Update. I did put the car up on jackstands and had the wife run it up to 40 MPH. I used a broom handle pressed against each rear wheel hub and also against the center differential. I had a hard time noticing where the sound was coming from. One thing that did stand out was that the left rear, USA drivers side, hub did sound different from the right. The left side sounded strange to me, almost crunchy. After the test I took off the wheels. I noticed the left side had a lot of rust on the large center axle nut and and threads. Almost like it had spent some time under water. The other side was clean like new almost. I'll have to check the car history to see if the right rear was ever replaced. I put the wheels back on and tried tried to rock from the top and bottom, but there was no sign of play. Even with play does the crunchy sound and the fact that the axle nut/threads look rust like they have been submerged sound like could be a wheel bearing/hub issue?

Also, when the car was run on the jack stands both the Check Engine and ABS warning lights came on. The ABS light did not come on at the next startup and after a couple more startups the Check Engine light went off.