Third differential installed after second one was in only 300 mi!!

[vonhiner]

Hey guys anyone else having these diff problems?? I like many others had my differential replaced about 5900miles after hearing the annoying whining noise around 40-45mph. Lockhart Cadillac Indianapolis,IN replaced the differential after changing the fluid to see if that would help(it didn't). After getting the car back I was happy until about 300 miles later backing out of a parking place at low speed cranking the wheel I heard this grinding rubbing noise. After keeping the car three more days I should have the car back tomorrow with another new rear end. They say the clutch pack went out of the rear end? Oh well, they paid for it and they also installed my new sub-frame bushings...I can't wait to check out the wheel hop issue, but now I'm a little afraid to get on the rear end too much. Chris Hiner

[StealthV]

Sounds like your rear end assembly didn't get any anti-slip additive either. Make sure they put some in next time or you'll be back again soon.

[Dave's V]

It is hard to fault the car for a mechanic's stupidity. No additive means dealer trip in the near future.

[DeputyDog]

Rick

Is there a tsb on the rear end anti slip additive. If so where would I go. I ask because I just had the rear end replaced and told the dealer abou the anti slip additive. They told me they would only do what GM says in the book, because this was there first rear end replacement.

Geoff

[MLV]

No additive=grinding=ruined differential very soon. Been there, done that.

[ctsvett]

Geoff, there is no TSB on this yet, because the dealers should be smart enough to make sure and read the proper section in the Shop manual. Many are not and read the CTS section (it's a combined manual) and then will say dumb things like "the V does not have a Limited slip diff" (sorry v-seriestech- not your dealer).

The car needs the limited slip additive...

Reed

[ntechnic]

This scares me, I accidently went 200 miles without the additive. Now, I know the additive is only a friction modifier for the clutches in the LS, and that bearings, gear faces, etc., don't need it. So I'm primarily worried about the clutches.

Oh well, I now know that you have to use the additive even with the grape stuff...

[CTSVLS6]

Had mine replaced at 10000 miles, whining real bad. The second one was making noise right from the start. The third one is getting louder all the time. They didn't put in the additive on the third one and it was making the same noise as yours, so after 1500 miles I changed the fluid and added the additive. That stoped the grinding noise when turing but the whine is still there and getting louder all the time.

[a64pilot]

Originally Posted by ntechnic

This scares me, I accidently went 200 miles without the additive. Now, I know the additive is only a friction modifier for the clutches in the LS, and that bearings, gear faces, etc., don't need it. So I'm primarily worried about the clutches.

Oh well, I now know that you have to use the additive even with the grape stuff...

Youv'e almost certainly not hurt anything in 200 miles. In other posi vehicles run without the additive I've seen them get so bad they will drag a tire in a turn and the clutches still weren't hurt. I assume the V dosen't exhibit this behaviour as the tires are so big and sticky the clutches catch it instead of the tires dragging. The additive doesn't hurt a thing if put in a diff that dosen't need it. It only hurts if it's needed and not there. It's cheap and very easy to add. I would just add it myself instead of having an argument with the dealer.
Any of you guy's that are getting new gearsets in their diff, remember the diff is the reason a new car should be driven at slow speeds and short trips the first 500 miles or so. If your gearset is new then it should be broken in again. I.E. <55 mph for 500 miles or so, yes it's painful, but necessary.
On edit: worn clutches usually won't exhibit any symptoms at all except one black mark on burnouts and a shudder type feeling in the car in slow speed, sharp turns. It would be the dragging/shudder feeling in parking lot speeds I would look for to show worn/sticking clutches

[Kadonny]

So are the factory cars coming out with or without the addative in the rear diffs?

[Seattle CTS-V]

Originally Posted by Kadonny

So are the factory cars coming out with or without the addative in the rear diffs?

Hmmm, I never thought to ask that question but that would pertain to me as my car is pretty new.