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Discussion Starter #1
Hello everyone, I've had my 2010 GT since new and it's been a great car but it's aging a bit. I've started to replace a few components here and there to keep her running well. Well, recently the rear control arms were replaced as the stock ones were clinging to life by a thread. I used the cheap SR performance control arms from American muscle which have poly bushings (at least I think its poly). The car is riding GREAT how ever the rear end is so loud it's almost unbearable. I know that "up grading" control arms make the rear end louder but good god. Is it safe to assume the rear end is going out as well? I have 4.10 gears in it but over all I haven't been to hard on this car at all, I've maybe dumped the clutch at around 2k rpm maybe 5-6 times in its life. It's not making any unusual noise, no clunking, it cruises fine, but I do notice that if I change lanes to the right the sound almost completely disappears. It also seems to drive nice and strong so really other than being very loud it seems okay.

I wanted to get some opinions here before I go to a shop and they charge me 200$ just to open and inspect my rear end.
 

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Discussion Starter #2
Also wanted to add that it doesn't get real loud until around 70+ mph. Anything under is pretty typical of what you would expect from a geared car
 

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Is it loud all the time, or only during coasting, or while slowing down? Mine is pretty quiet even at over 100+.
 

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Discussion Starter #5
No it's mainly loud at over 70 mph or so and while coasting. City driving it's pretty docile. It's always had some gear whine ever since I did the gears probably like 80k miles ago lol but it's especially bad now. I've read about some people getting very loud gear whine after doing control arms but this is horrible. My car is cammed off road x and bullet mufflers and I can very easily hear the gear whine over the exhaust.
 

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Discussion Starter #6
Sorry for the extra posting but I'm using my phone on here. Like I mentioned in my initial post the car seems to be driving fine, just loud as hell lol.
 

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Do you feel comfortable pulling the cover and looking at it?
 

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Discussion Starter #8
I've never done that, not to say I wouldn't do it. Don't you need some sort of pump to fill it back up with diff fluid?

I also haven't noticed the differential leaking, I've been parking in the same spot for years and it's actually clean.

I've asked a few local shops mainly power by the hour performance and it's 200$ to inspect and clean the diff but replacing parts varies from 400$ to over a grand. I've replaced quite a few things over the last few months, clutch + slave, rear control arms, front a arm or whatever it's called on the driver side, it starts to add up lol.
 

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Free Mouth Hugs
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Unfortunately that's the only way to figure it out (inspecting). Some people can give a good guess when they hear it.

I'd assume it's the bearings. Comp/carrier or axle shaft bearings. If the comp/carrier bearings are wore out it can effect the backlash.
 

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Free Mouth Hugs
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I couldn't tell you honestly. Never paid for them to be done and I only work on big diesel trucks (semi/dump) so pricing isn't the same.

In sure someone can help you on that tho!
 

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Discussion Starter #12
Cool, thanks for the help man. I guess it's time to save up another few hundred bucks again.

One more question, would it cost any more in labor to replace the 4.10 gears to 3.73s (assuming it's my bearings)? I wouldn't mind saving a few bucks in gas from gearing up and I have a set of 3.73s laying around.
 

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If it's just bearing, it wouldnt cost anymore than just the new gears and the install fee w/oil.
 

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Other than price of the gear set and install kit, I cant see it being much more. They have to re set them up anyways if they are replacing all the bearings.

But then again it is a shop so who knows! lol
 

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Discussion Starter #15
Do the bearings come in the gear install kit? I'm on American muscle now and they have the gear install kit and trak lock rebuild kit, i have the 3.73 and rear gear bearing as well.
 

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Rebuild and install are usually different. But may contain some of the same stuff.
 

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Also, if your gears were making noise after the initial install, you should have had them adjusted then. Now that you have 80K miles on them I would think that they are beyond the point of trying to get them quiet.

I paid $300 for an install of a complete rear end and ring and pinion with all the bearings and such. I bought all the parts. Last time I had a new diff thrown in it was only $175 because I had the axle out of the car and was a bench job. This is by one of the more reputable 4x4 shops in my area. They welded my axle tubes and relocation brackets for $50 more dollars at the same time.

If you think it is bearings get the master rebuild kit. It will have everything they will need. I think I got mine from JEGS and they were Timken bearings.
 

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Discussion Starter #18
I thought gear whine was kind of an unavoidable thing once you swap in New gears? I had a ls1 ws6 before this and it had gear whine, not as bas but still had it. I understand where you're coming from though, i gues next time I'll know what to look out for.

I recorded a video it's really loud and I noticed in the video there is indeed a weird sound but could not hear it in person. Guess the camera hear differently lol.

https://youtu.be/78-9uZSkgx0
 

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Discussion Starter #20
It wasn't anywhere as bad as it is now. But yeah there was a little whine back then not much but there was. Guess I'll know for next time
 
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