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08-23-2008 11:55 PM #1
Roaring sound- Differential, Bearing or Tire ?
Experts please weigh in:
99 323i, MT, 110 K- had a diff fluid change a couple months go and a problem started this week. What is hear is a roar from 30 mph that does not change much in volume. Sounds almost like driving over grooved concrete- the noise is driving me nuts. Makes no difference if the car is in gear or neutral or accelerating.
I raised the car and see no leaks in the diff, CV boots. Checked the bearings by rotating the rear wheel with parking brake off- The rear wheels turn OK- less freely than the fronts and the drivers rear seems a bit tighter still but neither wheel was binding or making any noise.
Don't see anything odd with rear tires and the tires have ~ 15000 miles on them with no vibrations or any other issues. It does sound like a bad tire I once had but that turned out to be a broken belt but that tire was new. To add to the confusion one rear tire had a puncture in the tread a month ago- it was nail and was fixed with a rubber plug- the plug looks fine.
Could this be related to the diff ?
08-24-2008 09:25 AM #2
- chesapeake, VA, United StatesMember No: 59049
- Join Date
- Nov 2002
- Rep Power
if it doesn't change with acceleration or...
deceleration and no change with turning right or lrft, I'm thinking a bad tire. Differential problems usually don't present themselves all of a sudden. They're more of a gradual increase in noise. That is unless you sheared a tooth off of a gear or something similar.
08-24-2008 10:04 AM #3
08-24-2008 12:24 PM #4
08-24-2008 04:08 PM #5
- North Brunswick, , United StatesMember No: 4529
- Join Date
- Nov 2000
- Rep Power
What kind of tires?
I have Goodyear GS-D3's on my car and am going to have to dump them soon because they are VERY noisy. My ears cannot take it much longer. Goodyear cannot seem to make a tire suitable for a BMW that is a daily driver. Although they have 15K miles on them they also still have 8/32" or more still left, and in perfect condition otherwise, no cupping or unusual wear. Anyone need some autocross tires (225/50-16's)? They handle like crazy but the noise is unacceptable.
You problem may nust be tires. Can you switch to another set just for testing (obviously that are already mounted)
08-25-2008 08:36 AM #6
UPDATE- Roaring sound- Differential, Bearing
Did some extensive checking:
- Changed rear tires to a different set (I had a spare tire + wheel set)- the roaring sound is till present. So, I have ruled out the tires (Kumho Ecsta ASX)
- Differential fluid level and color is as expected
- I can hear a "wub-wub" when making right turns at 40 mph or higher (on ramps). Don't hear that on left turns or on right turns at slower speeds.
- Noise definitely coming from the rear
08-25-2008 08:56 AM #7
08-25-2008 09:15 AM #8
08-25-2008 10:05 AM #9
08-29-2008 01:32 AM #10
- Liberty Center, OH, United StatesMember No: 68241
- Join Date
- Mar 2003
- Rep Power
My wife's 2004 325ci was making a very loud rump rump rump sound as it was driven even though the tires were not near the wear bars yet. It had the Continental ContiSportContact in the 225/45-17 size. The noise was loud enough that I could hear her coming down our road on her way home. Tread was probably at 20-30% so I being a titewad did not want to put tires on it will spring when the snows come off.
Well I used the car for travel to Wisconsin to bring a sailboat to Indiana across lake Michigan and barely made it 20 miles until I lost the sidewall in the P/S rear tire. I don't drive the car much but it felt as if one tire was low on pressure and I was headed to a service station prior to getting on the toll road to check pressures when the tire failed.
I replaced the tires with the Bridgestone Potenza RE760 Sport. Tires feel good, noise is gone and Mama's happy!
1986 911 Carrera
1994 Chevy C2500
2005 MINI Cooper S (4 sale)
08-31-2008 10:03 AM #11
Re: Roaring sound- Differential, Bearing or Tire ?
It sounds like you have eliminated the tires by changing to another set. I went thru this recently also. While I'm not sure what is meant by a "roaring" noise, I had what sounded like tire problems turn out to be a wheel bearing. If I remember correctly special tools are needed making it out of the reach of many. The good news is it was only @$300 at my indy. The other side failed about 15K later.
08-31-2008 10:27 PM #12
09-08-2008 10:17 AM #13
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