BS!! The first time I complained about mine the Technician told the service writer that he was tired of working around the problem and replaced the clutch packs and upgraded the fluid. That was 9,000 miles ago and it has not made any more noise!!

 

I seriously doubt he replaced the clutches, do you have any idea what is involved in that if the diff stays in the car? My guess is you got a fluid change. The diff itself used to be a Non Service item, I am not sure if it still is but I do not know why it would change. In other wards if there were mechanical problem, it came out and was replaced. I have rebuilt more of these diffs then I can count, and I can promise this clutch issue is normal in a LSD diff. Heck I have a F-350 I pull my trailer with and it pops in you back out of the driveway in the mornings. It is the nature of the beast.

 

double dose of additive fixed mine, 1yr plus with no chatter.

 

Okay, so this is my first time owning a Vette. I purchased an 05 Z51 and had it delivered because I could not drive it due to the snow in the area. I have the chatter in the rear when backing it hard left/right out of the garage.

So, from what I hear, change the fluid or see if the fluid has been changed and drive figure 8s in a parking lot. OR, just leave it alone? So confusing!

 

Ken,
This does become confusing because there are so many opinions and most come from individuals who hear it from somewhere else.
You do not need to do anything, you can do figure 8's but that will only last as long as you drive the car this time. If the clutches are binding when you turn you can add another bottle of additive but I would not put more than that. You are not hurting anything with them popping it is the nature of a LSD or POSI diff. It is going to pop in the morning when backing out of the garage because all of the lubrication is in the bottom of the diff. It will go away or become less evasive once you drive and the diff gets warm and the oil starts working its way up into the diff and clutches. Whatever you do not let someone convince you that you need to replace the clutches, that is snake oil.

 

I have an 05 and it chattered. I read many, many posts and TSB's as well. I recommend u do the same. After all that I opted to go the auto hobby shop put it on a lift and change the fluid myself, before getting too carried away. I opted (after much reading) for the Royal Purple synthetic. I immediately cranked her up and proceeded to do the figure 8's right in the parking lot. The manager came out and wondered what in the h___ I was doing so I had explain this important step to him. He nodded, shrugged and went back inside. Anyway if there is any noise now I can barely notice it. I don't work for Royal Purple but it was a unanimous choice. Now I see why. I do agree with the figure 8's. I suspect that step is usually omitted or forgotten.

 

The reason why you do the figure 8's is because you are constantly in a turn which when you turn the clutches break loose and because you are moving forward the oil is working its way in them. This is a quick method, the same as if you drive and make allot of turns. When the car sits the oil still drains off the clutches, you are only leaving a thin film of oil on them. Depending on how much additive you are using is how much of it is concentrated on the clutch plate. A TSB is a customer complaint, if you read all the TSB's they have them ranging from rattle in the door panel. The clutch issue is not a issue where there is actually something wrong in the diff. I can tell you what effect that TSB had though. When the ZO6 came out GM had a awesome clutch setup that requires less preload to keep the torque constant in it through the life of the diff, but because of the complaints the material has changed along with the actual amount of disks inside the unit. Now the plate has a material that is approx. 20 thousands bonded to a steel disk instead of the previous clutch. I have already had a new disk show up with the material glued on wrong and one missing. I hope that GM engineers see this problem and go back to the good performance setup and not let the suits redesign a part because of customer complaints that don't fully understand what the fix is or that fact that it is just the nature of the beast. Kind of like complaining that a ZO6 might ride a little rough. I will try in the next couple days to post a picture of what the new clutch looks like vs. the old one. I can't speak for the rest of the diff rebuilders out there, but I rebuilt more Getrag Diff units in the C5/6's then what any Chevy dealer in the country combined has had apart. I have never had a street diff damaged from a clutch issue, and I have only had one race diff that was damaged in the clutch area and I don't remember what had caused it but it was one from David Farmer, he might remember it but something had seized in it and it melted the spider gears in it. Can anyone on here actually say there diff was damaged by the clutch chattering, I would be interested to see it.