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Discussion Starter #1
'05 owners....I had the diffential whine issue. Picked the car up today after dealer replaced the differential. The whine is greatly reduced. There is still a very faint whine 40-50mph under light decelleration. Also the back lash seems to be reduced. I am pleased with the replacement differential, most would not even notice any noise, I think I am probably just super sensitive to any rearend noise due to having the whine issue and diff. replacement.
If you have noticable rearend whine you can take your car to the dealer, Pontiac has a program to correct the problem...they replace the entire Differential assembly. If the problem exists it will likely happen at 40-50mph under light acceleration and/or deceleration. :cheers
 

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I have an 04 and had mine replaced for whine on off throttle. Couple thousand miles later whines worse with the foot on the gas. :cheers
 

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Discussion Starter #5
johnebgoode said:
Mine is on order through dealership. Now its just a waiting game......!!
It took 2 months to get mine in. I plan to run it 500-700miles and then drain the gear oil. The GM synthetic gear oil and additive is expensive but I think an oil change after initial break in is a good practice because when gears break in they generate fine metal particles as the teeth polish the contact areas...just my opinion :cheers
 

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04gtolover said:
I have an 04 and had mine replaced for whine on off throttle. Couple thousand miles later whines worse with the foot on the gas. :cheers
Take it back. That just means they got a differential that was not laser set. All of the new replacements will be set properly, which means that it should completely eliminate the whine.
 

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NT91 said:
How many 05 GTO's have the diffential whine issue? 50%

What is the root of the whine?

I have 900 miles on my GTO no whine as of yet.

It was described to me by our GM rep. That the manually set rings in the differential are not set properly and they vibrate against each other. That causes the whine and eventually ends up hurting the rear end.

This guy normally is spot on with his information, but I had a hard time believing that our rearend would vibrate like that.

Anyways he went on to say that the new differentials are set with a laser guided machine and they are always perfect.
 

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Discussion Starter #10
cat1055man said:
'05 owners....I had the diffential whine issue. Picked the car up today after dealer replaced the differential. The whine is greatly reduced. There is still a very faint whine 40-50mph under light decelleration. Also the back lash seems to be reduced. I am pleased with the replacement differential, most would not even notice any noise, I think I am probably just super sensitive to any rearend noise due to having the whine issue and diff. replacement.
If you have noticable rearend whine you can take your car to the dealer, Pontiac has a program to correct the problem...they replace the entire Differential assembly. If the problem exists it will likely happen at 40-50mph under light acceleration and/or deceleration. :cheers
UP-DATE...CRAWLED UNDER THE CAR TODAY TO LOOK AT THE NEW DIFFERENTIAL INSTALLATION. ONE OF THE MOUNTING SOCKETS, CAST INTO THE REAR COVER, FOR THE R.H. SPEED SENSOR IS DAMAGED. LOOKS LIKE THE UNIT WAS DROPPED OR DAMAGED IN SHIPMENT, THE SPEED SENSOR IS MOUNTED AND FUNCTIONS BUT THE BROKEN CAST COVER IS NOT ACCEPTABLE. DIGITAL PHOTOS HAVE BEEN E-MAILED TO THE SERVICE MANAGER. I WILL FIND OUT WHAT NEXT STEPS ARE NEXT WEEK.
 

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cat1055man said:
It took 2 months to get mine in. I plan to run it 500-700miles and then drain the gear oil. The GM synthetic gear oil and additive is expensive but I think an oil change after initial break in is a good practice because when gears break in they generate fine metal particles as the teeth polish the contact areas...just my opinion :cheers
Sounds like a good plan of attack. Will put that into my PM schedule. Thanks.
 

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Mine picked up the whine @ around 4000 miles. Whine comes in around 80 mph and drops out around 87 mph. Problem is, that is the speed I normally drive, so I get to hear it alot. :eek:
 

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Discussion Starter #14
johnebgoode said:
Sounds like a good plan of attack. Will put that into my PM schedule. Thanks.
J.B.Goode,
I am told that it is critical to use the proper GM lubricant 75w-140 synthetic p/n 89021809 and the fiction modifier p/n 89021958. The modifier has a very strong chemical odor, never smelled anything quite like this stuff. Expensive too $27 / qt. list and about $17ea. for the friction modifier. There is aftermarket stuff thats probably o.k but I am sticking with the GM product just to be sure. :cheers
 

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dealernut said:
It was described to me by our GM rep. That the manually set rings in the differential are not set properly and they vibrate against each other. That causes the whine and eventually ends up hurting the rear end.

This guy normally is spot on with his information, but I had a hard time believing that our rearend would vibrate like that.

Anyways he went on to say that the new differentials are set with a laser guided machine and they are always perfect.
Yea right PERFECT tell your rep to come to my dealership and ill show him one thats been replaced and he can tell me that it is perfect when its whining gonnig down the road.
What sucks is we had another on in at my dealership that had its diff replaced and was whining again.TAC said replaced the diff but the gm emgineer said dont replaced it. Theres no fix its supposed to be like that. So i dont even bother to bring my car back in to get it look at cause gm wont do anything about it.
 

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cat1055man said:
I am told that it is critical to use the proper GM lubricant 75w-140 synthetic p/n 89021809 and the fiction modifier p/n 89021958.
many of us have had problems with the GM lubricants and the FM. Dealers always say its critical to use their product. Many have change after a couple thousand miles and not impressed with the GM synthetic that came from the factory. Those switching to aftermarket synthetics have done well and some have elminated the noise in the rear end. Royal Purple makes a great product that does not need the FM. RP is what the GTO-R uses.
 

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Differential noise

I have the noise problem, with just over 600 miles on the GTO. Question for those who work closely with GM-Pontiac, is there a service bulletin yet on the differential noise issue? I would like to refer my dealer to the bulletin if there is a bulletin. Thanks, Al
 

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cat1055man said:
J.B.Goode,
I am told that it is critical to use the proper GM lubricant 75w-140 synthetic p/n 89021809 and the fiction modifier p/n 89021958. The modifier has a very strong chemical odor, never smelled anything quite like this stuff. Expensive too $27 / qt. list and about $17ea. for the friction modifier. There is aftermarket stuff thats probably o.k but I am sticking with the GM product just to be sure. :cheers
Meanwhile its now January and I'm still waiting for the diff to come in....since Thanksgiving!!! I think it's time to wake up the parts dep't at the dealership.
 

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Discussion Starter #19
johnebgoode said:
Meanwhile its now January and I'm still waiting for the diff to come in....since Thansgiving!!! I think it's time to wake up the parts dep't at the dealership.
J.B.Goode......It took me 2 months to get mine. The new differential is quieter but I can still hear a very slight whine decellerating around 45 mph and a very slight whine accelerating thru 50-55 mph range. I plan to put some miles on it and see if it gets louder. Good luck with yours :cheers
 

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cat1055man said:
J.B.Goode......It took me 2 months to get mine. The new differential is quieter but I can still hear a very slight whine decellerating around 45 mph and a very slight whine accelerating thru 50-55 mph range. I plan to put some miles on it and see if it gets louder. Good luck with yours :cheers
I just called Dealer, they have part. Appointment for 1/23.
 
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