1997 Oldsmobile Bravada Front Axle Low on Gear Oil, Whining

Tiny
NTL1991
  • MEMBER
  • 1997 OLDSMOBILE BRAVADA
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 149,000 MILES
My 97 Bravada has been making a whining sound that occurs above about 30-35 MPH and continues on into the 80+ MPH range. The sound stops when accelerating, but as soon as speed is maintained or deceleration occurs, the whine comes back. I checked and replaced the rear differential oil (A Gov-Lock Posi-traction differential) and nothing changed. The gears looked fine but there was considerable play in the drive shaft and yoke which was corrected by replacing both original rear U-Joints. The sound still existed, but a shimmy on acceleration was corrected. I then checked the front differential fluid and it was low, it took about 3/4 of a quart. The noise quieted down, but it still exists. My question is: If I see no fluid leaking, where would it go, and, What would an approximate cost be for repairing this problem? Thanks, Nick.
Monday, April 20th, 2009 AT 1:42 AM

7 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Well the fluid went somewhere. Did you have any axle work done or anything like that? Otherwise I would look at the axle seals and the pinion seal make sure they are dry. If all this looks good then I would remove the front cover and service it. Meaning drain the fluid and clean out the old fluid and put in all new fluid. It may be that is just needs to be changed and while you are in there you can look over the gears and see what they look like too. Let me know what you find.
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Monday, April 20th, 2009 AT 11:41 AM
Tiny
NTL1991
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I checked the level of the fluid when greasing the front end last week and I noticed a sludgy buildup on the end of the front passenger side axle. I noticed it because there was a label there the oil and road grime was covering it. I haven't checked back to see if any has accumulated there again.

If that is gear oil, then the axle seal is gone, correct? If the oil has been leaking for a while, bearings would be worn down, making a noise, right?

Is there any way to determine whether an axle bearing is gone compared to a carrier or pinion bearing?

Thanks,
Nick
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Sunday, May 3rd, 2009 AT 10:47 PM
Tiny
RACEFAN966
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OK if the gear oil is leaking from that seal then yes you need to replace that seal. As for weather or not the bearings are bad depends on weather or not it makes the noise when it is full. If it is quiet when it is full then I would say replace the seal and put in fresh gear oil and just keep an ear to it and it is stay's quiet then let it be.
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Wednesday, May 6th, 2009 AT 10:00 AM
Tiny
NTL1991
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Well, when I filled the differential back up and even after other checks to see if its full, there has always been noise. It has never gone away, full or not.

Nick
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Thursday, May 7th, 2009 AT 7:21 PM
Tiny
RACEFAN966
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Well I would take it to a differential shop and have it check unless you have a rack were you can listen to it to make sure the noise is coming from the differential. It may also be a hub bearing too have you checked them for noise?
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Friday, May 8th, 2009 AT 9:00 AM
Tiny
NTL1991
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Yes, I can throw the truck on the rack and use a stethoscope to figure out if its the front or rear. Or if it's from the wheel bearing or actual differential.
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Friday, May 8th, 2009 AT 11:51 AM
Tiny
RACEFAN966
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Good then if you would do that. Let me know what you find. Thanks.
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Saturday, May 9th, 2009 AT 8:15 AM

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