Humming Noise
01-21-2017, 05:10 PM
#1
Staging Lane
Thread Starter
Humming Noise Hey Guys,
I bought an '01 WS6 with 75k on it this fall and one of the things that has developed since I put about 900 miles on it was a hum from the back of the car.
The humming is based off the speed of the car, not the revs of the engine, and becomes audible after about 40-50 mph.
I thought it was the diff, but I had a master mechanic open up the diff and he said everything looked good. We filled it up with fluid again and off I went.
I then got an alignment (car was pulling left), but that also did not fix the humming (and the car still pulls left a little bit).
A couple suggestions that I received was to take it back and have the alignment double checked, that the frame might be bent, or that the U-joint needs to be replaced.
I was wondering if anyone had any other thoughts or suggestions to share.
Many thanks in advance...
Mike
I bought an '01 WS6 with 75k on it this fall and one of the things that has developed since I put about 900 miles on it was a hum from the back of the car.
The humming is based off the speed of the car, not the revs of the engine, and becomes audible after about 40-50 mph.
I thought it was the diff, but I had a master mechanic open up the diff and he said everything looked good. We filled it up with fluid again and off I went.
I then got an alignment (car was pulling left), but that also did not fix the humming (and the car still pulls left a little bit).
A couple suggestions that I received was to take it back and have the alignment double checked, that the frame might be bent, or that the U-joint needs to be replaced.
I was wondering if anyone had any other thoughts or suggestions to share.
Many thanks in advance...
Mike
05-04-2017, 10:38 PM
#4
Staging Lane
Thread Starter
05-04-2017, 11:01 PM
#5
Most of the time I hear hum at X to X speeds, its usually within the rear end, my dads ford 88 had a hum at around 45 and higher it stayed constant at those speeds. Turned out to be a bad rear axle shaft and bearing.The axle had a good groove carved into it, after that it was totally quiet. are you sure its a hum and not a whine whirring type of noise?
Now my truck made a whine at 45 mph and higher only under acceleration, that turned out to be bad pinion bearings which have turned out to be a massive head ache as am trying to rebuild it for the first time with help from the guys here.
that's just my two cents as you stated its coming from the rear, I still have my OEM U-joints at 222,000 miles, and am hard on them.
Now my truck made a whine at 45 mph and higher only under acceleration, that turned out to be bad pinion bearings which have turned out to be a massive head ache as am trying to rebuild it for the first time with help from the guys here.
that's just my two cents as you stated its coming from the rear, I still have my OEM U-joints at 222,000 miles, and am hard on them.
05-04-2017, 11:11 PM
#6
Go by a vibration gauge. You can get cheap mechanical ones and run the car to find the frequency of the vibration. You can then do the math to figure out what part of the car is spinning at the right speed to be the cause. Allows you to narrow it down to very few things for cheap and easy.
05-06-2017, 08:26 AM
#7
TECH Fanatic
iTrader: (5)
OP, did your mechanic listen to the pinion and axle bearings with a stethescope on the rack with someone holding the accerlator at 40-45mph? You can't see a bad bearing with a cover off inspection. Carrier and pinion bearings experience gauling and pitting after the hardness wears off, poor oil condition, over usage etc. you need to isolate the noise at a given mph then on the rack at that same speed, it'll take 2 to do this.
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07-18-2018, 06:25 PM
#9
Staging Lane
Thread Starter
OP, did your mechanic listen to the pinion and axle bearings with a stethescope on the rack with someone holding the accerlator at 40-45mph? You can't see a bad bearing with a cover off inspection. Carrier and pinion bearings experience gauling and pitting after the hardness wears off, poor oil condition, over usage etc. you need to isolate the noise at a given mph then on the rack at that same speed, it'll take 2 to do this.
