rear diff noise returns

[DJ-Silver 2SS]

I've been through the fluid changes, figures 8s, and a differential change. When they replaced the entire center section, the noise went away. It's all about the paint on the gears that gets on the clutch packs.

[djnice]

Originally Posted by DJ-Silver 2SS

I've been through the fluid changes, figures 8s, and a differential change. When they replaced the entire center section, the noise went away. It's all about the paint on the gears that gets on the clutch packs.

Any idea why some have this issue and others don't?

[strych9]

Originally Posted by DJ-Silver 2SS

I've been through the fluid changes, figures 8s, and a differential change. When they replaced the entire center section, the noise went away. It's all about the paint on the gears that gets on the clutch packs.

Where did you get this information? I've installed many gearsets, but I've never seen one painted.

The noise can be caused by not having enough friction modifier, or the clutches are too tight. Either way, if you can live with the noise, it's better from a performance standpoint. The noise does no harm whatsoever.

If you can feel chatter when you turn...that requires attention.

[Sven59]

Originally Posted by DJ-Silver 2SS

I've been through the fluid changes, figures 8s, and a differential change. When they replaced the entire center section, the noise went away. It's all about the paint on the gears that gets on the clutch packs.

I had the center section replaced and the noise came back, went away after they performed the service bulletin.

[PNYSLAR]

Originally Posted by Trackman

X2
At 1500 miles is a complete waste of money. Hell I may never change the oil in the diff. Seems when people mess with it it makes noise.

Mine started this @5k

[DJ-Silver 2SS]

Originally Posted by strych9

Where did you get this information? I've installed many gearsets, but I've never seen one painted.

The noise can be caused by not having enough friction modifier, or the clutches are too tight. Either way, if you can live with the noise, it's better from a performance standpoint. The noise does no harm whatsoever.

If you can feel chatter when you turn...that requires attention.

My apologies for the use of the word paint. The "paint" that is used to measure the spacing between the gears is what I am taking about, and the manufacturer that gm got the rear ends put to much paint inside. When you drive your cars and heat up the gears, the "paint" comes off and embeds into the clutch packs for the posi.

[DJ-Silver 2SS]

Originally Posted by djnice

Any idea why some have this issue and others don't?

It depends on what lot came from the manufacturer. I don't know and haven't heard specifically if it is in a specific grouping.

[Sven59]

Originally Posted by DJ-Silver 2SS

It depends on what lot came from the manufacturer. I don't know and haven't heard specifically if it is in a specific grouping.

One of the theories is that the lashing compound caused the issue, hence the flush and fill and the figure 8s. That is just opinion but it fits.

[rzrbck_zl1]

I just had the repeated flush/fill/figure 8's done @ 7000 miles. Seems to have taken care of the problem, at least for the time being...

[IROC U]

I got the car back and it seems to be fine now. However our last few days have been warmer. It only makes the noise when the car is completely cold and less than 60 degrees (backing out of my garage in the morning). When I would turn around backing out of my garage I could actually feel the grinding noise through the steering wheel. Previously after a few minutes of driving (when it warms up) the noise would go away. Last fall I had to leave the car with the dealer overnight for them to see what I was talking about. My dealer told me yesterday that if it did it again they would replace it.

[NightmareZL1]

Originally Posted by qniknam

What is this groaning that you're talking about, are you talking about the wooshing/kind of whistling that comes from the rear end? Does it bother you that much.

Yes, a noise coming from a a new car, that cost me over 60k, does bother me quite a bit.

The noise appeared at about about 1700 miles. It was a humming that sounded off on slow tight turns. By 4000 miles is was much louder. At 6000 miles the noise was embarrassingly loud in a parking lot/structure and on tight u turns the rear started binding and chattering - the wheels would skip a bit. People would stare at the car for the wrong reason...

Dealer replaced items per the TSB. The noise was gone for 1 day. next day it was back. It was the same as in the beginning (1700mi). I did about twenty circles right and left, the noise went away. The next day it was back again. 1000 miles later and it is still groaning.

I just have to find the time to visit the dealer again. I am not looking foward to driving a loaner chevy POS malibu again (yuck!)

[CAM....ZL1]

Well mine didn't do it til I had the diff. serviced at 1500 mi.
Now at 10500 mi. it makes a slight humm on tight turns and has for several thousand miles. The faint humm doesn't bother me, I have had it
to the strip, on high speed runs and driven it just like it's ment to drive
with no issues and no increase in noise from the rear.

[ZL1Reaper]

It would be nice to have somebody from GM to comment on this. Say Fbodfather?
We all keep wondering this or that but nobody seem to have a clue to what causes the noise / grinding.
Is it harmful? Will it stop eventually?
Is it annoying?
Yeah, it's annoying! $60000 car. Come on!