Rear Drone Noise, like Plane Propeller
12-23-2016, 05:51 AM
#1
Rear Drone Noise, like Plane Propeller
Over a 2 month period, a noise developed and built up. As I drove, it seemed to come from the direction midway between the middle of the rear seat and rear driver wheel. I have a professional background in dynamics testing - so this was most concerning and intriguing.
Initially, it was a droning noise, much like a plane propeller drone, that appeared at speeds 60 mph, but pronounced at 70+.. Then as time progressed, a whir sound developed at 30 mph that built up till the drone appeared at the high speed. I followed the following investigation process:
~ going into neutral, going up hills, etc. I determined it was speed related.
~ turning left or right didn't change the sound.
~ no vibration was felt in the floor, steering, etc. at the various speeds noise was heard.
~ changing traction control, etc. changed nothing.
I contemplated maybe something went wrong with a recent rear diff fluid exchange, that I was now using Michelin Primacy tires (20,000 miles on 'em) and that the RL was now 10 years old. I hoped it wasn't something major like this thread's focus on the prop shaft.
At the mechanic, with a stethoscope, one could hear there was a wheel bearing problem. But for me, this didn't explain the propeller drone noise.
Further exploring, what was also interesting was that some vibration/noise could be heard in the wheel strut. It was minor, but present, and it gave me hope. While the mechanic puzzled, I noted that the wheel strut has flexible deflectors for protection and this was where I heard the drone noise emanating from (almost too good to be true?). The compound noise might just be sourced to the wheel bearing?
Replaced the rear wheel bearing. Saved $100 by buying the part from OEMacuraparts.com. It's been some days now, all is well. It seems that the drone/droning propeller noise, giving me anxiety that this would be a major repair, may just have been those little flexible deflectors going into resonance from the wheel bearing vibration.
Initially, it was a droning noise, much like a plane propeller drone, that appeared at speeds 60 mph, but pronounced at 70+.. Then as time progressed, a whir sound developed at 30 mph that built up till the drone appeared at the high speed. I followed the following investigation process:
~ going into neutral, going up hills, etc. I determined it was speed related.
~ turning left or right didn't change the sound.
~ no vibration was felt in the floor, steering, etc. at the various speeds noise was heard.
~ changing traction control, etc. changed nothing.
I contemplated maybe something went wrong with a recent rear diff fluid exchange, that I was now using Michelin Primacy tires (20,000 miles on 'em) and that the RL was now 10 years old. I hoped it wasn't something major like this thread's focus on the prop shaft.
At the mechanic, with a stethoscope, one could hear there was a wheel bearing problem. But for me, this didn't explain the propeller drone noise.
Further exploring, what was also interesting was that some vibration/noise could be heard in the wheel strut. It was minor, but present, and it gave me hope. While the mechanic puzzled, I noted that the wheel strut has flexible deflectors for protection and this was where I heard the drone noise emanating from (almost too good to be true?). The compound noise might just be sourced to the wheel bearing?
Replaced the rear wheel bearing. Saved $100 by buying the part from OEMacuraparts.com. It's been some days now, all is well. It seems that the drone/droning propeller noise, giving me anxiety that this would be a major repair, may just have been those little flexible deflectors going into resonance from the wheel bearing vibration.
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TonyCD (01-11-2017)
