[beech2000]

Hi All,

We'll Christmas is now over and thought I'd do some internet research on an on going noisy differential in my
wife's 2000 Safari hence the new user tag on this forum.

The noise is most noticeable on deceleration during turns but somewhat nosiy during straight interstate runs but not bad.

We bought the vehicle new 8 years ago and changed the rear end fluid now twice. The first time the fluid change was performed by Carl Black GMC here in Kennesaw and the second time about 3,500 miles ago by me. Both times the limited slip additive was used.

The vehicle now has around 80K and the higher levels of noise are starting to worry me. While I had the cover off I decided to take the carrier out and have a gander. I found no overheating if bearings, and axle bearings appear normal. With out having the backlash gage and tooling, My inspection was limited to visual only.

Thoughts anyone?

 

[astro355]

Hello beech2000,

How did the pattern on the gears look? Commenting on the reflective side of each tooth, was the reflective area centered on even tooth or was it off to a side?

10 bolts are notorious for getting noisy with age. The noise is produced from the meshing of the pinion and ring gears. Even if you had a tool to measure the backlash, you should leave it alone. Making adjustments to worn gears will create more noise. Even removing the carrier and reinstalling it the exact way it was before removing it, can create more noise.

Is the noise being transmitted thru the floor of the van?

 

[gtkane]

Can you give more details about the noise?
Is it howling, clicking, grinding,etc? Is it more pronounced when turning left or right?

 

[97TurboAstro]

My '97 had a howl to it. Turned out to be the pinion bearing.

Couldn't see any wear if we only had the cover off. we had to remove all the guts to see the problem. Once we got that pinion out, it was obvious - both bearing and race were pitted.

 

[beech2000]

Hello beech2000,

How did the pattern on the gears look? Commenting on the reflective side of each tooth, was the reflective area centered on even tooth or was it off to a side?

10 bolts are notorious for getting noisy with age. The noise is produced from the meshing of the pinion and ring gears. Even if you had a tool to measure the backlash, you should leave it alone. Making adjustments to worn gears will create more noise. Even removing the carrier and reinstalling it the exact way it was before removing it, can create more noise.

Is the noise being transmitted thru the floor of the van?

Wear pattern looked normal (Centered) to me but no expert.

The noise does not transmit thru floor.

Thanks for the reply all and sorry for the long delay in thread response. Holidays etc...

 

[beech2000]

My '97 had a howl to it. Turned out to be the pinion bearing.

Couldn't see any wear if we only had the cover off. we had to remove all the guts to see the problem. Once we got that pinion out, it was obvious - both bearing and race were pitted.

Very cool. Did the ring and pinion gears require replacement due to the bearing change out?

 

[97TurboAstro]

My '97 had a howl to it. Turned out to be the pinion bearing.

Very cool. Did the ring and pinion gears require replacement due to the bearing change out?

no new gears required. Just had to re-align everything...

 

[astro355]

You can re-use them but the gears will still be noisy. I guess it depends on how much and what kind of noise you can put up with.

 

[beech2000]

I forgot to mention the large amounts of metal powder on magnetic drain plug. So the question is whether its bearing material, gear wear or both.

I also forgot to mention that the grinding whine noise is mainly in a decelerated turn in either direction.

 

[beech2000]

Well I have gone and done it now.

Wife said fix the noise or else new car is coming.

So back at it.

Removed cover and magnet was covered in fine powder.

I removed both axles and outer wheel bearings. Bearings were fine but will replace.

Pulled out the carrier and bearings are fried. Right side is even pitted.

I spun the pinion by hand and all feels normal with no play.

Question:
Can I replace the bearings and reassemble as is? or do I need to measure backlash and shim

*The differential is GM's posi traction type with the clutches.

The vehicle now has 92K Miles on it.

Thanks
Kevin

 

[Matrixx]

It's always a good idea to check everything when you install new parts in the rear end. Nothing is really quite the same after wards. Personally, I would replace the pinion bearing here as well if it had any real miles on it, but that's just me.

Let us know how things workout beech2000, Thanks.

 

[beech2000]

Sorry for the delayed posting. Just now got a chance to close out this thread.

After many miles of running miss noisy the vehicle is now perfect! Yes the growling noise is finally gone. Turned out to the rear differential carrier bearings the whole time.

I had local NAPA machine shop replaced the bearings. I reassembled the differential and serviced with high quality synthetic oil and noise is gone gone gone.

Thanks for all the feed back.