rear diff moan

[rlem00]

so about a month ago I took my car in due to the rear diff moan some of us are hearing. Told the service guy what was wrong and what to do to fixe it. He had not hear of the issue but they took a look and wow, wait for it...I was right. They replaced the gear oil in the diff and the moan when away. This is something I would not have minded doing on my own but as it's under warrenty, figure it woudl be best to have this documented. Well, about 2,500 miles later the moan came back. It also seems as though the rear end is tight until I get it warmed up, hard to explain, buy we all know you know your car and how it acts. I'm going to drop it off at the service department on Monday to have them look at it again. Anyone have any ideas on why it would have started back up? I'd like to have a few things to throw out at the service guy's by Monday. This is a daily driver and other than the occasional stop to get around someone, I drive fairly conservative...well as conservative as you can drive a 400hp car.

[Dans2SS]

Since you had to tell them what was wrong could they have not know what gear oil the Camaro used and maybe put the wrong stuff in? I don't like bashing dealers cause I know some really good ppl int he business, but I also have seen some really crappy ones. I'm not putting much past them with my last few experiences.

[Skyblu]

Originally Posted by rlem00

so about a month ago I took my car in due to the rear diff moan some of us are hearing. Told the service guy what was wrong and what to do to fixe it. He had not hear of the issue but they took a look and wow, wait for it...I was right. They replaced the gear oil in the diff and the moan when away. This is something I would not have minded doing on my own but as it's under warrenty, figure it woudl be best to have this documented. Well, about 2,500 miles later the moan came back. It also seems as though the rear end is tight until I get it warmed up, hard to explain, buy we all know you know your car and how it acts. I'm going to drop it off at the service department on Monday to have them look at it again. Anyone have any ideas on why it would have started back up? I'd like to have a few things to throw out at the service guy's by Monday. This is a daily driver and other than the occasional stop to get around someone, I drive fairly conservative...well as conservative as you can drive a 400hp car.

mine did the same thing, replaced fluid started doing it again took back three times now they claim they can't hear it,it's my imagination. Still doing it coming up on 24,000 miles I am going to take it back and make them hear it before my warranty goes out!!! I'ts the clutches in the rear sticking. GM has had this issue on and off for years with posi rear ends. I had a silverado in the early 80's that did the same thing.

[Skyblu]

P.S there is a TSB for this to drain and replace fluid and put posi non slip add in which they did the first time.

[Rock-It Man]

I hear the diff when I turn sharply in reverse, backing out of a parking spot. So what?

A limited slip is not going to be silent. As long as it's not banging, all is well.

[race29]

Originally Posted by Skyblu

mine did the same thing, replaced fluid started doing it again took back three times now they claim they can't hear it,it's my imagination. Still doing it coming up on 24,000 miles I am going to take it back and make them hear it before my warranty goes out!!! I'ts the clutches in the rear sticking. GM has had this issue on and off for years with posi rear ends. I had a silverado in the early 80's that did the same thing.

Had an 83 Z28 only a few years old at the time and had rear end problems...moaned...whined...replaced the gears a couple of times traded it quiet not sure how long it lasted...definitely they had some rear issues. The rear never went just was always loud.

[jtzako]

Mine did make some noise at first. I replaced the fluid and added the friction modifier and it cleared up. (mostly) It still does make some noises when reversing and turning at the same time. However, it doesnt sound like anything is broken and is probably not fixable.

[Scott@Bjorn3D]

Yeah I have changed the rearend lube twice on mine in 30K and she will quite down for about 2K and then back to moaning.

[Mustang Killa]

Originally Posted by Rock-It Man

I hear the diff when I turn sharply in reverse, backing out of a parking spot. So what?

A limited slip is not going to be silent. As long as it's not banging, all is well.

Same exact issue.. Im a little concerned, I put in the royal purple and still have it..maybe add an additional non friction fluid..

[rlem00]

thing that worries me is the moan is appears to be caused by friction, which is typically bad unless you are talking about breaks. That gets into service life and if there is a design flaw which would cause a decreased service life of a driveline component, they need to pay for the replacement of said componant not me.

[DAVET1LT]

Originally Posted by rlem00

thing that worries me is the moan is appears to be caused by friction, which is typically bad unless you are talking about breaks. That gets into service life and if there is a design flaw which would cause a decreased service life of a driveline component, they need to pay for the replacement of said componant not me.

What they may be forgetting to do is a series of figure 8's after they put the new fluid and modifier in the rear end. I had an SS Trailblazer that had this issue and they replaced the fluid two times with the modifier added. Someone mentioned to me the figure 8's and I made sure they did after the last fluid replacement and never had the issue again. Besides, I traded it anyways.

[jtzako]

Originally Posted by DAVET1LT

What they may be forgetting to do is a series of figure 8's after they put the new fluid and modifier in the rear end. I had an SS Trailblazer that had this issue and they replaced the fluid two times with the modifier added. Someone mentioned to me the figure 8's and I made sure they did after the last fluid replacement and never had the issue again. Besides, I traded it anyways.

I did that after changing mine and eventually the 'moan' in reverse came back.

[DAVET1LT]

Originally Posted by jtzako

I did that after changing mine and eventually the 'moan' in reverse came back.

Bummer man. I unloaded the SS Trailblazer after the 3rd Rear Diff fluid change and I believe it would more than likely have come back if I kept it. I hear a lot of complaints from the Corvette owners on this same issue and I saw where one fellow had the issue with his truck. I believe once the moaning starts and then quitens with the fluid change two or three times, that the clutch paks in the rear end and the bearings are all burned at that point and need to be replaced and GM should replace the compoents up to 100K as that is considered power train.

[rlem00]

I did the figure 8's myself after leaving the shop, just to be sure