I am getting a strong vibration & Howling that starts at exactly 50mph. I have replaced the wheel bearings. I notice at around 55mph when I go over a rise in the road, the howling subsides until the car again bottoms out.
I am thinking its maybe the bearings in the differential or drive shaft, but why it would start at 50mph is well beyond me.
I hope there is someone out there with the answer.
Thanks
You need to say what year and model you have, and mileage. Has anything in the driveline or chassis been replaced/repaired recently? Did the noise start before you replaced the (rear, I assume) wheel bearings? Have you tried rotating the tires?
Could be the differential. Worn ring & pinion gears tend to have harmonics that are strong at certain speeds and manifest as a howl. This is sometimes attenuated by chassis parts that are close by, which begin vibrating too, perhaps because they are loose and/or a rubber bushing is worn through. Driveshaft noises tend to be loudest when accelerating or decelerating, and cyclical when cruising. Does it get worse the higher you go above 50mph, or does it subside?
If you have a back seat, it might be useful for you to ride there (with someone else driving the car at 50mph) and put your ear down to various places forward and rearward, left and right, etc. to see if you can pinpoint the source more closely.
Given the new wheel bearings I'd suspect the drive shaft's universal joints or carrier bearing(s). (I don't specifically know what it has.)
Ring and pinion gears inside the differential can be noisy at certain speeds when their mesh isn't perfect. But they don't vibrate and the condition isn't sudden - it typically is found in new cars and very gradually worsens over years.
That's not to say that the pinion gear's bearings shouldn't be considered suspects in this search.
I'd first check the driveshaft.
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