98 Wheel Bearing Howl
ew0001
11-25-2007, 11:22 PM
I have a 98 Suburban with 4 wheel drive and the 5.7L motor. Over the past few months, I have developed a whine similar to a differential noise in the front end.
The symptoms when driving are:
* High pitch/frequency whine is worst at about 40-45 mph in any gear and is speed dependent, not RPM dependent.
* Turning to the right at speed (transfering vehicle weight) makes it seem to get louder, while turning to the left makes it subside significantly. It seems to be wheel load depended.
I originally thought it may be tire noise or the front differential based on the sound (it sounds just like a differential that isn't set right or is worn). I spent some time today troubleshooting. I put a spare tire on which I know does not have agressive tread with no change in the noise.
I disconnected (and removed) the front drive shaft and drove it, still no change. Since it was in 2wd mode, the front diff was not turning at all, so I think this rules out the diff. I also verified the fluid was clean and up to the proper level in the diff.
I also jacked up the rear end by the axle and ran it at the same speeds and did not hear the noise. Since I didn't have a vehicle load on the tires, I guess I can't totally eliminate the problem in the back, but it certainly sounds like it is coming from the front.
It cannot be heard with the windows down or outside of the vehicle. It sounds like a resonance transmitting up through the frame or body with the windows up.
I inspected the front wheel bearings and didn't find any real issues with excessive play. It was a little dry feeling but nothing out of the ordinary.
I suspect it is my left front wheel bearing based on the limited info I have.
My question is has anyone else had a similar noise in the front end and replacing the wheel bearing assembly has eliminated the problem? These are expensive bearings that are $300+ so I want to make sure this is likely to be the culprit before I invest time and money to wheel bearings.
-Ed
The symptoms when driving are:
* High pitch/frequency whine is worst at about 40-45 mph in any gear and is speed dependent, not RPM dependent.
* Turning to the right at speed (transfering vehicle weight) makes it seem to get louder, while turning to the left makes it subside significantly. It seems to be wheel load depended.
I originally thought it may be tire noise or the front differential based on the sound (it sounds just like a differential that isn't set right or is worn). I spent some time today troubleshooting. I put a spare tire on which I know does not have agressive tread with no change in the noise.
I disconnected (and removed) the front drive shaft and drove it, still no change. Since it was in 2wd mode, the front diff was not turning at all, so I think this rules out the diff. I also verified the fluid was clean and up to the proper level in the diff.
I also jacked up the rear end by the axle and ran it at the same speeds and did not hear the noise. Since I didn't have a vehicle load on the tires, I guess I can't totally eliminate the problem in the back, but it certainly sounds like it is coming from the front.
It cannot be heard with the windows down or outside of the vehicle. It sounds like a resonance transmitting up through the frame or body with the windows up.
I inspected the front wheel bearings and didn't find any real issues with excessive play. It was a little dry feeling but nothing out of the ordinary.
I suspect it is my left front wheel bearing based on the limited info I have.
My question is has anyone else had a similar noise in the front end and replacing the wheel bearing assembly has eliminated the problem? These are expensive bearings that are $300+ so I want to make sure this is likely to be the culprit before I invest time and money to wheel bearings.
-Ed
J-Ri
11-26-2007, 04:29 PM
Swerve left and right at the speed you can hear the noise the most (of course be careful not to do this with other vehicles present, or fast enough to roll it over). If it gets louder on right turns (weight shifts to left), I would say you are most likely correct that it is the LF wheel bearing.
old_master
11-26-2007, 04:48 PM
There are two sets of ball bearings in each hub assembly. When turning the vehicle, it loads one set and unloads the other. Raise the front wheels, rotate the wheels by hand while using a stethoscope to determine which hub is causing the noise.
Chevy-SS
12-14-2007, 07:45 AM
Did you ever fix this? I have a similar problem with my '98 K1500 4WD Silverado. Though my noise is not exactly like yours, I too suspect wheel bearing.
What did you do to fix yours?
thanks
What did you do to fix yours?
thanks
ew0001
04-06-2008, 11:49 PM
Well, I finally located the source of the howling. After deciding to live with the noise for a while since the wheel bearing assembly is about $300+, it started to get more noticeable, especially when under load, but it would go almost completely away under deceleration or turning left.
I found the noise to be the rear differential. I taped a wireless baby monitor transmitter to various points on the chassis (lower control arm, transfer case, and rear axle). I listened to the monitor while driving. Don't laugh, this worked really well!!! When it was taped to the rear axle, the noise was horrendous.
I took the rear cover off the rear diff and found the carrier to be loose. I checked my pattern and backlash and found it to be excessive (ring gear too far away from the pinion). Further removal of the carrier led to the discovery that the left carrier bearing (the one closest to the ring gear) had spun and the inside race was spinning on the carrier which should have been a press fit. So now I'm at the stage to attempt to repair it and re-shim it hoping to get the pattern set and crossing my fingers that it doesn't still howl.
I have purchased a new bearing, dimpled the carrier in several places with a punch to try to get a tighter fit against the bearing inner race, and used green retaining loctite on the inner bearing race to the carrier in hope of preventing the bearing from spinning again, especially considering the carrier is compromised at this point.
My question is: is this a common occurance with a GM 8.5 10 bolt axle to spin carrier bearings? What causes this? Are there any known fixes (besides upgrading the carrier to an aftermarket)?
I'll post again with more results when I get it back together.
-Ed
I found the noise to be the rear differential. I taped a wireless baby monitor transmitter to various points on the chassis (lower control arm, transfer case, and rear axle). I listened to the monitor while driving. Don't laugh, this worked really well!!! When it was taped to the rear axle, the noise was horrendous.
I took the rear cover off the rear diff and found the carrier to be loose. I checked my pattern and backlash and found it to be excessive (ring gear too far away from the pinion). Further removal of the carrier led to the discovery that the left carrier bearing (the one closest to the ring gear) had spun and the inside race was spinning on the carrier which should have been a press fit. So now I'm at the stage to attempt to repair it and re-shim it hoping to get the pattern set and crossing my fingers that it doesn't still howl.
I have purchased a new bearing, dimpled the carrier in several places with a punch to try to get a tighter fit against the bearing inner race, and used green retaining loctite on the inner bearing race to the carrier in hope of preventing the bearing from spinning again, especially considering the carrier is compromised at this point.
My question is: is this a common occurance with a GM 8.5 10 bolt axle to spin carrier bearings? What causes this? Are there any known fixes (besides upgrading the carrier to an aftermarket)?
I'll post again with more results when I get it back together.
-Ed
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