How often Differntial Lube Change?
Team Owner
Joined: May 2004
Posts: 82,175
Likes: 1,319
From: McKinney TX
St. Jude Donor '21-'22-'23-'24
My 2006 owner's manual doesn't mention ever changing it. Here's what it says to use if the fluid level gets a little low.
SAE 75W-90 Synthetic Axle Lubricant
(GM Part No. U.S. 12378261,
in Canada 10953455) meeting
GM Specification 9986115. With a
complete drain and refill add
4 ounces (118 ml) of Limited-Slip
Axle Lubricant Additive
(GM Part No. U.S. 1052358,
in Canada 992694) where required.
See Rear Axle on page 5-51.
(GM Part No. U.S. 12378261,
in Canada 10953455) meeting
GM Specification 9986115. With a
complete drain and refill add
4 ounces (118 ml) of Limited-Slip
Axle Lubricant Additive
(GM Part No. U.S. 1052358,
in Canada 992694) where required.
See Rear Axle on page 5-51.
Team Owner
Joined: Sep 2000
Posts: 24,964
Likes: 2,680
From: Far NW 'burbs of Chicago
St. Jude Donor '13
There is indeed a special GM diff lube, it now contains the LS additives.
Can't recall the part number, but it's standard on 2009 & later, said to be good for any GM posi setup from any year.
I changed mine at 5k and plan to change again at 50k, but that's probably serious overkill.
Can't recall the part number, but it's standard on 2009 & later, said to be good for any GM posi setup from any year.
I changed mine at 5k and plan to change again at 50k, but that's probably serious overkill.
Le Mans Master
Joined: Oct 2000
Posts: 6,461
Likes: 701
From: Sausalito CA
I'll go w/ above.
Change initially at 5K then every 50K.
That would be fantastic maintenance.
Yes there is a "special" GM oil. I think it is nearly $30 a bottle and you need a bottle and half when changing.
Change initially at 5K then every 50K.
That would be fantastic maintenance.
Yes there is a "special" GM oil. I think it is nearly $30 a bottle and you need a bottle and half when changing.
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Race Director
Joined: Dec 2006
Posts: 12,290
Likes: 2,858
From: Fort Worth, Texas
Haha, ain't that the truth. Rule of thumb is 30k, but it really dependent on hard you drive the car. IE High heat from high rpms while road racing the car and that interval needs to be shortened considerably.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,104
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I also don't understand how road racing (closed loop, not SSCC) would create more heat in a limited time at lower average speeds than longer duration driving at higher speeds on mountain roads or IS highways. Differential RPM is directly related to road speed, not engine RPM.
I'm not trying to be a smart-***, but I've never changed rear axle fluid on any car as a maintenance procedure and I've had cars with 230K miles without an issue.
Melting Slicks
Joined: Oct 2010
Posts: 2,314
Likes: 4
From: Cape May, NJ; Guntersville, AL; Orange Beach, AL
Every 30k really??? I had a 03 Duramax with a Banks kit making 800+ ft/lbs and the rear lasted 150k. I used it to tow our 33 foot boat and our 2 John Deers that weigh 10k+ a peice probably 30k miles. I couldn't even find info in the manual so I'm not going to mess with mine. If it goes it goes. I think Corvettes get "over serviced" all the time.
Last edited by gunterwalker; May 10, 2011 at 08:29 PM.
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
Where would I find this rule of thumb and how and when were they created, or is this tribal knowledge without scientific analysis? The manuals (owner's and shop) don't address changing the fluid ever unless there is damage or leaks.
I also don't understand how road racing (closed loop, not SSCC) would create more heat in a limited time at lower average speeds than longer duration driving at higher speeds on mountain roads or IS highways. Differential RPM is directly related to road speed, not engine RPM.
I'm not trying to be a smart-***, but I've never changed rear axle fluid on any car as a maintenance procedure and I've had cars with 230K miles without an issue.
I also don't understand how road racing (closed loop, not SSCC) would create more heat in a limited time at lower average speeds than longer duration driving at higher speeds on mountain roads or IS highways. Differential RPM is directly related to road speed, not engine RPM.
I'm not trying to be a smart-***, but I've never changed rear axle fluid on any car as a maintenance procedure and I've had cars with 230K miles without an issue.
AMSOIL Gear Lube “White Paper” (2 MB pdf file)
I submitted my CTS-V factory fill diff fuid to Blackstone at only 10k miles and they weren't very impressed with the wear and recommended changing (which I had already done):
2006 Cadillac CTS-V Used Oil Analysis Factory Fill Differential Fluid
Personally, for a street car, I use the 30k thumbrule as well, though at the track I do it about once a season. For the AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT), AMSOIL recommends 50k in severe service, which I would argue the Vette is.
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Racer
Joined: Jul 2009
Posts: 340
Likes: 0
Every 30k really??? I had a 03 Duramax with a Banks kit making 800+ ft/lbs and the rear lasted 150k. I used it to tow our 33 foot boat and our 2 John Deers that weigh 10k+ a peice probably 30k miles. I couldn't even find info in the manual so I'm not going to mess with mine. If it goes it goes. I think Corvettes get "over serviced" all the time.
I gotta agree with you on that!
Andy
Race Director
Joined: Sep 2000
Posts: 11,118
Likes: 1,889
From: Missouri City, TX
..........Personally, for a street car, I use the 30k thumbrule as well, though at the track I do it about once a season. For the AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT), AMSOIL recommends 50k in severe service, which I would argue the Vette is.
I think 30k is a reasonable change interval unless the diff is already experiencing clutch chatter and in no case would I let it go beyond 50k.
Race Director
Joined: Dec 2006
Posts: 12,290
Likes: 2,858
From: Fort Worth, Texas
Every 30k really??? I had a 03 Duramax with a Banks kit making 800+ ft/lbs and the rear lasted 150k. I used it to tow our 33 foot boat and our 2 John Deers that weigh 10k+ a peice probably 30k miles. I couldn't even find info in the manual so I'm not going to mess with mine. If it goes it goes. I think Corvettes get "over serviced" all the time.
Race Director
Joined: Sep 2000
Posts: 11,118
Likes: 1,889
From: Missouri City, TX
Race Director
Joined: Oct 2005
Posts: 14,999
Likes: 199
From: Bay Area Ca.
The reason DTE recommends yearly oil changes is due to the increase of clutch pack material in the oil. This is with the clutch pack upgrade.
The disc are made up of a softer material for better bite, hence more wear fallout.
The disc are made up of a softer material for better bite, hence more wear fallout.
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
I also don't understand how road racing (closed loop, not SSCC) would create more heat in a limited time at lower average speeds than longer duration driving at higher speeds on mountain roads or IS highways. Differential RPM is directly related to road speed, not engine RPM.
That said, I change mine about once every two seasons. I have no idea how many miles. I'm with you, we definately tend to "over service" our cars around here. But part of that is the fun with working on (under?) them. At least for me
