Whining Xterra

I’ve notice a pronounced whine coming from the passenger side rear of my 2005 4x4 Xterra. The whine begins at about 63 mph and fades out over about 70. It seems loudest at 67 or so but only when the drive train is loaded (i.e., the noise immdiately stops if I take my foot off the accelerator or when costing downhill).

I took it into a service center for diagnosis. They checked the rear differential fluid and reported to me that it looked “muddy.” They suggested replacing it. I agreed but it really didn’t reduce the noise. There next course of action is to replace the rear differential. I’m reluctant for two reasons: (1) I’m not noticing any other symptoms. In fact, except for the noice, the vehicle is running great. (2) My mpg has not changed even a little bit. I’d expect some noticable mpg hit if my rear differential was failing. Any thoughts?


CK Hanson

You may not notice any other symptom for some times.

If you had grown up in the 1950’s, you would know that differential whine was common. One of the cars my parents owned was a 1954 Buick. The rear end started whining when the car had about 70,000 miles. It didn’t affect the gas mileage or the performance of the car. My dad finally had a new ring and pinion gear at 110,000 miles when it got so loud he couldn’t stand the noise any longer.