:banghead: Well.....Went to my dealership yesterday and had the lube changed in the diff. It seems, according to my Service Manager, I have normal wear on the diff internals and a normal amount of metal on the drain plug after 6000 miles and five more months of driving. I must admit that after my trip to Ft Wayne in December, I have not heard the diff whine again sooooooooooo...... it's time to beat the cubes and see if the parts fly. I'll be heading to "DTE" soon to get Stage III installed and put the "V" back on the dyno to get some good numbers. I warned my dealership to order the diff now and have it on hand.......I know I'm going to need it somewhere down the road!!! :banghead:

Unless it whines where you can hear it above normal radio volume or a conversation, I wouldn't worry about it. There is no guarantee the 2nd dif would be better.

Hey, maybe you will get lucky and have my experience. The dealer forgot to add the posi additive to the rear when they changed the fluid. I received the same treatment/ story you got, until they forgot the posi additive (it was not on the detailed parts bill).

3 weeks later, the rear was singing the 'change me' song, loud and clear...1 week later, new rear !!

Why in the heck would anyone want to change out the rear before it actually breaks. Seems to me that would be the best time to take it to the track and launch the car like its supposed to be launched knowing that it is no biggie if it breaks. I think the board has made some people unnecessarily paranoid about the rear. i know I strain trying to listen to mine some times now.

Why in the heck would anyone want to change out the rear before it actually breaks. Seems to me that would be the best time to take it to the track and launch the car like its supposed to be launched knowing that it is no biggie if it breaks. I think the board has made some people unnecessarily paranoid about the rear. i know I strain trying to listen to mine some times now.

I know what you're saying.

I think I heard the whine for the first time yesterday after about 100 miles of interstate driving.

well if she aint singing
BEAT HER!!!
:D

Hey, maybe you will get lucky and have my experience. The dealer forgot to add the posi additive to the rear when they changed the fluid. I received the same treatment/ story you got, until they forgot the posi additive (it was not on the detailed parts bill).

3 weeks later, the rear was singing the 'change me' song, loud and clear...1 week later, new rear !!

Actually, I talked to Cadillac but the additive is not required with the new fluid part #. It already contains the additive. My dealer even showed me the page in the CTS V manual, the parts man said it is not required either.

GM can deny a claim if it has the new fluid and additive in the rear end. That is why my dealer wouldn't put it in. I switched to redline anyways which contains the additive and since it meets at least GL-4 standards it is legal.

Funny that they replaced the rear because of the additive. i was under the understanding that the additive is the same ole stuff they have been using for years and that it just keeps the rear from "chattering" which has no ill affects on the rear, just makes a god aweful well..."chattering" noise.

Not true according to a posted question from about 6 months ago on this very board. Not sure what the 'new' additive is, but when I brought my car in the whine was there, the parade clunk had advanced to a parade bang, and when I told them the whole thing sounded like it was on the edge, the dealer said 'we will change the fluid and see what happens'.

I was fine with that, I was not looking for a new rear just because I read about it on this board..

As stated, within 2 weeks the rear went from a slight whine to a very audible high pitched whine that got louder with acceleration. I posed that very question on this board and received feedback that it WAS a requirment.
The mechanic admitted to never changing the fluid on a posi unit.

As an aside, when they changed the rear they also changed the bushing that has been attributed to the parade clunk and my car has been tight since.
The rear end change was worth that alone, as it was getting embarrassing it was so load.

I say beat the car like a drum, if the rear is acting up or not. Especially if it is under warranty. Nobody I know buys a muscle car to drive around like a funeral hearse. I for one, would not wait for the car to be failing, to go to the track and finish it off. Besides, with the wheel hop on this car, I would not bother taking to the track. I just take the Grand National.