: Rear Diff, Axles, Wheel Hop, What Should I do ?



SevillianSTS
07-27-11, 04:28 PM
2007 CTS-V
72k miles.

Still covered under factory powertrain warranty and also have an extended warranty for 4 more years.

I definately have the diff "whine" Was thinking about taking it in and complaining about it.

Considering getting the GForce axles.

Was driving in the rain today she was hopping so bad the rearview mirror moved out of position.

- Should I get the axles now ? or should I "kill" the diff now get it replaced and then get axles ?

I'm really impressed with how many people are pleased with these axles, but I don't want to put them on now, blow the diff and then possibly get voided on the warranty.

Any ideas suggestions ?

Thanks

darkman
07-27-11, 04:41 PM
I would complain about the differential whine until it gets replaced.

If you get the axles after that, remove any aftermarket markings and/or spray paint them OEM black. Dealers are more likely to miss or ignore aftermarket parts that do not sitck out. Since the axles really serve to prolong the life of the other drive line components they should not serve to void a warranty anyway, but an argument avoided is argument won.

GDPossehl
07-27-11, 05:06 PM
If you plan on keeping that current exhaust setup in there, you need to consider heat wrap or shielding on the adjacent exhaust pipes by the differential. I see complaint after complaint about rear diff noise and the few people that have wrapped the exhaust with DEI heat shielding (google (http://www.google.com/search?q=dei+heat+shield&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)) have had great results. Myself included.

SevillianSTS
07-27-11, 05:39 PM
Stock exhaust right now, looking into going Borla in the near future. Do you still recommend wrapping the pipes with the Borla cat-back system?
If so, where do you wrap it, just around the diff ?

tweeter81
07-27-11, 06:20 PM
If you plan on keeping that current exhaust setup in there, you need to consider heat wrap or shielding on the adjacent exhaust pipes by the differential. I see complaint after complaint about rear diff noise and the few people that have wrapped the exhaust with DEI heat shielding (google (http://www.google.com/search?q=dei+heat+shield&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)) have had great results. Myself included.

I have been on this forum for a long time and have never heard of anyone do this to help with the diff issues. I guess it couldn't hurt, but it doesn't address the root cause of the problem.

The thing that causes the diff to fail is a cracked case, due to excess wheelhop causing deformation to the point where the aluminum just can't hold up anymore. Heat is not the issue here.

If you take away the wheelhop (at least in 95% of the situations...all IRS cars will still hop in the rain), you take away the reason that the cases fail.

CadzillaTN
07-27-11, 07:20 PM
I think people are just trying to cut down on noise with this mod, not prevent failure...There's clearly merit to keeping the diff temp down, otherwise they wouldn't sell a $1500 refrigerator unit that bolts to the bottom...

PISNUOFF
07-27-11, 07:22 PM
I powered through wheel hop for two years and never broke my '07 diff. I'd get the axles and take off the Gforce stickers. They look stock enough to get by the dealer and take care of almost all the wheelhop.

lollygagger8
07-28-11, 10:53 AM
Diff doesn't whine because of heat, it's because the TQ our motors put on the Pontiac Soltice Diff gears. They don't make any noise right when they are new. Once you put em through a few spirited driving sessions....viola! Whine.

Wrapping your exhaust won't do anything but get you laughed at.

Get axles. I'll have some bada$$ DSS axles for sale in the classifieds soon. As soon as Gforce sends me the 9" rear end kit I've been waiting forever for.

CadzillaTN
07-28-11, 11:22 AM
Diff doesn't whine because of heat, it's because the TQ our motors put on the Pontiac Soltice Diff gears. They don't make any noise right when they are new. Once you put em through a few spirited driving sessions....viola! Whine.

Wrapping your exhaust won't do anything but get you laughed at.

Get axles. I'll have some bada$$ DSS axles for sale in the classifieds soon. As soon as Gforce sends me the 9" rear end kit I've been waiting forever for.

Agreed on point 1. I have had more diffs than anyone, and I can say that a couple of them seemed to start whining after only one or two pedal mashes, albeit with no hop. Sad really..

2 others howled within 2 weeks of break in granny driving under 4k rpm.

Axles might prevent you from shattering a case but they're not going to do squat to prevent whine.

Buttom line, all versions are weak under-engineered pieces of crap.

rand49er
07-28-11, 12:07 PM
By all means, get your diff replaced and get axles, too. Be aware, however, guys are still getting WH in wet conditions even with axles. Personally, my car sees precious little rain, so I can't share any personal experience on that one.

SevillianSTS
07-28-11, 01:54 PM
Thanks guys for all the input. I'm probably gonna go piss and moan about the whine and try to get it replaced, and then throw on some axles soon.

JimmyH
07-28-11, 06:48 PM
I think the whine originates from distortion in the carrier (or the gears, I forget which) It's been discussed here to death.

garrettg
07-31-11, 11:08 PM
I have the axles and had the dealer replace the diff shortly after the same dealership installed the axles. I don't drop the clutch in my car and stay away from anything that puts instant stress on the drivetrain. I have a few k on the new diff and its been very quiet. I also had a new trans installed due to a bent output shaft making some noise as well. The 100k powertrain has paid off in a big way. The axles make a difference both wet and dry, but have not been to the track for the ultimate test.

GDPossehl
08-01-11, 01:24 PM
Wrapping your exhaust won't do anything but get you laughed at.


My result speaks for itself.

CadzillaTN
08-01-11, 02:16 PM
Can't polish a turd.