Cracked differential cover?

[Grave_bait_ss]

Hey all. I have a 2011 2ss 6.2 6 speed manual. It only has 450whp.

My question is this… 30,000km ago i had the bearings in the rear replaced at the dealership (used car was covered under warranty) they used OEM replacements. (I asked to pay the difference for more beefed up options but the tech “forgot” to replace it with such. They had the car two weeks already and I would have had to pay new parts and labour to fix it again.

The car was making some weird noise which sounded like it was coming from on top of the transmission. Sounded like a loose bolt, with a loose washer vibrating around it.
I thought pilot bearing, throw out bearing, no. Push on the shifter or give it gas rolling and push in the clutch a little no change in noise. Its the worst in 3+ gears under load. Not even hard load.
No idea what this noise is. My friend works at the dealership so i drive it there and ask if they could have a look. A tech puts it on the hoist, we look and the rear end is covered in fluid. On inspection there is a 2” crack beside the “”arm” or pivot point that has that bushing in it on the rear diff cover.
I asked how that would have happened, tech says “sending it too hard”. I said I haven’t been doing so at all lately. Looks at my tires “your tires are bald”, (chinese rubber with more than 30,000k on them on the back). I said “no, i have not, how much rubbers in my wheel wells?” He looks then has no rebuttal. The last time i did send it hard, was new years. Tires are bald, they are summers, it was maybe 50* outside (southern canada) and the road was wet. I drive this car everyday, not on the heavy snowy days or the days the roads are snow covered. (.obviously not getting far with it to begin with).

Nobody has seen that at the dealership before. When they rebuilt the rear, that rubber bushing was not changed. GM doesn’t even offer a replacement part (had to order myself from summit as well as the bushings) for it, nor offer the bushings. Car quest, napa etc all the same.

Online there is little info that i could find. I tried this forum with little luck (i may not be posting in the right area or looking in the right place). What i could find online says over 500whp, improper torque on the bolts making them uneven and putting undue stress on the part. The other cause was physical trauma from smashing a curb, huge pothole etc. i’ve not done anything to cause trauma like that.

Anyone have any ideas? Any tips for me when I change it out beginning of the week? (If i drop the diff fluid and there is any metal, shavings etc. chevy will replace what they rebuilt including labour (which for that job quote was 10 hours at 150$ an hour, which is not happening) then charge me the difference. If i take the cover off and anything's broken, chevy will still replace their work from then out (i have to take pics then get it towed back to dealership from the shop i used to work at, whom is lending me a bay + hoist). The red line on the pic if it loads to attach is about where it is and the length of it.

How would this happen? Is it common to have happen? Likely hood of it happening again? And anything else anyone has to add?

(Tech legit also asked me if i replaced the coil overs to adjustable ones I thought they were stock on an ss but maybe everything i read is mistaken &#128514

Thanks for the help.

[bottletalk]

what mods does it have to get it to 450rwhp? does it have any suspension mods? trailing arms? toe rods?
ps:the red line that resembles the crack is not your diff cover, it's the subframe/cradle.

[Grave_bait_ss]

I bought it used. The ford dealership it came from didn’t know much other than it has a mild cam (guy approached me at the car wash saying hey that was my friends car, it has a cam blah blah do you like the car?)borla attack exhaust (high flow cats, mufflers) and thats pretty much all they could tell me. I had it on a dyno because nobody could tell me anything. Unless the company told me the wrong numbers. 467 was its best run (i just rounded it yo 450 to be sure it wasn’t too much for said part)

( It doesn’t have a tune in it (it needs one) it pops and bangs like it has a tune. Overly obnoxious loud. Not that any of that means much)

The crack is BEHIND the subframe. The sec pic shows the crack through a hole in that piece.

[acammer]

Maybe I'm missing it - but I'm not seeing a crack. That opening in the mounting tab is normal. Here are a few pictures for reference. The leak looks to simply be the rear cover itself, likely not perfectly sealed to the housing. I'd dump the fluid (looks like it needs it) and then remove the diff, remove, clean, and reinstall the cover, and get some fresh fluid in there.

[Grave_bait_ss]

This is where its cracked on the actual diff cover. That you can’t see. Diff cover looks like this, where i drew in black is the location of the crack.

I’ll take a better photo when i go look at the car again this afternoon. Right beside that support that holds the rubber bushing there is a crack…….

(Fluids getting changed, bushings are getting changed, gaskets etc. and anything else that needs after its removed)

Why do they crack here is the question? Has anyone else had it happen? I also live in Canada but it hasn’t even been that cold here.

[Tajefe Couple]

Somebody jack it up on the rear diff with a floor jack instead of where you are suppose to put a jack on each side of the car?

[gtstorey]

Originally Posted by Tajefe Couple

Somebody jack it up on the rear diff with a floor jack instead of where you are suppose to put a jack on each side of the car?

But they do it that way on Roadkill all the time.

[Grave_bait_ss]

Originally Posted by Tajefe Couple

Somebody jack it up on the rear diff with a floor jack instead of where you are suppose to put a jack on each side of the car?

Car has never been jacked up at any point, other than drive on hoists since I’ve owned it. That cover was off 30,000k ago when they rebuilt the diff and they said they didn’t see anything wrong with it.

[acammer]

Originally Posted by Grave_bait_ss

This is where its cracked on the actual diff cover. That you can’t see. Diff cover looks like this, where i drew in black is the location of the crack.

I’ll take a better photo when i go look at the car again this afternoon. Right beside that support that holds the rubber bushing there is a crack…….

(Fluids getting changed, bushings are getting changed, gaskets etc. and anything else that needs after its removed)

Why do they crack here is the question? Has anyone else had it happen? I also live in Canada but it hasn’t even been that cold here.

Gotcha - that makes more sense. I haven't seen one break/crack before, but it it probably is the weakest/highest load area on the cover, so if there was going to be a failure in the cover, that area makes sense. I sure wouldn't think it's temperature related.

I ran the LPW cover when I had the stock differential - definitely beefier. Not sure what sort of life you put your diff though, but I put several through pretty hard use, and while I've broken many other parts, I never hurt a cover. Definitely weird - like someone else said, maybe it's been lifted there at some point in it's like and fatigued it.

[bottletalk]

maybe the last time it was serviced the tech dropped the cover or it was cracked from before and he just sealed it up???it is just cast! no suspension/chassis upgrades to support the HP mods???
u should figure out what's done to your car and what the car needs before you hammer down.... regardless sh*t happens and parts break.

[Grave_bait_ss]

I had questioned about the tech compromising it when it was off. (Like they are going to admit anything).
I requested before it left for them to pull the plug and drain the fluids. They did so this am and i went to check on it before they threw it out. Thousands of shiny soft grains of material stuck to the drain plug and the magnet i put int he tub. Soo they are covering taking everything apart again. Looking at whats going on inside. Replacing what they fixed last time. Inspecting everything else. Putting the new bushings in and the new diff cover.

I suggested maybe it did have a hairline crack or something in it from previous today and they said it was a possibility.

[Grave_bait_ss]

Originally Posted by bottletalk

maybe the last time it was serviced the tech dropped the cover or it was cracked from before and he just sealed it up???it is just cast! no suspension/chassis upgrades to support the HP mods???
u should figure out what's done to your car and what the car needs before you hammer down.... regardless sh*t happens and parts break.

I inspected the car when i bought it. Everything other than exhaust and rear wheels looks stock. There are no branded parts under there. All factory assembly paint looking etc. just looked while it was on the hoist again. The tech i had this time didn’t even know it came with adjustable suspension……. Soo needless to say I didn’t bother taking much of what he said seriously.

i’ve had the car a year…. And put 30,000k on it before anything broke. Didn’t just buy it jump in and hammer down the street. I’m trying to find the previous owner to see what he all had done to the motor and if anything else was upgraded. It had factory upgraded suspension. I’ll attach build sheet…..

[bottletalk]

Originally Posted by Grave_bait_ss

I inspected the car when i bought it. Everything other than exhaust and rear wheels looks stock. There are no branded parts under there. All factory assembly paint looking etc. just looked while it was on the hoist again. The tech i had this time didn’t even know it came with adjustable suspension……. Soo needless to say I didn’t bother taking much of what he said seriously.

i’ve had the car a year…. And put 30,000k on it before anything broke. Didn’t just buy it jump in and hammer down the street. I’m trying to find the previous owner to see what he all had done to the motor and if anything else was upgraded. It had factory upgraded suspension. I’ll attach build sheet…..

you had it dyno'ed @467rwhp, thats roughly 140hp more then stock....thats a lot lot of power added onto a platform that snaps axles on stock builds and im sure the og owner didnt add the power just for the sound...umm, maybe he did but anyway thats a lot of axle snapping wheel hopping going on so you should accomodate the chassis to work with the power or this will keep happening....dont know bout the diff cover, thats a first for me but then again possible.

what your calling adjustable suspension could mean something totally different then what people familiar with cars call adjustable suspension...i have never heard of an option available to have adjustable suspension(compression, rebound or ride height)

ps:not trying to be a dick

[Grave_bait_ss]

Originally Posted by bottletalk

you had it dyno'ed @467rwhp, thats roughly 140hp more then stock....thats a lot lot of power added onto a platform that snaps axles on stock builds and im sure the og owner didnt add the power just for the sound...umm, maybe he did but anyway thats a lot of axle snapping wheel hopping going on so you should accomodate the chassis to work with the power or this will keep happening....dont know bout the diff cover, thats a first for me but then again possible.

what your calling adjustable suspension could mean something totally different then what people familiar with cars call adjustable suspension...i have never heard of an option available to have adjustable suspension(compression, rebound or ride height)

ps:not trying to be a dick

Not taking it that way. (Internet doesn’t allow people to hear someones tone, voice etc. If people read something with the thought someones being a dick automatic its offensive. If people read something open minded and to learn its taken much better. Thank you for clarifying)

He had zero idea you could adjust coil overs on a camaro, nor adjust any of the suspension…….. I’m not a licensed mechanic, nor do I work for GM and say I work on them, but know nothing of the options the cars come with? I have a female friend in the office of a car shop, who owns a newer one than I do and she even knows…… can’t fix her own car. But knows. Guess I just thought or expected someone st the dealership would know this.