Differential fluid change???
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,810
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From: Door County, WI
Differential fluid change???
A question... just talked to a dealer about having my coolant changed on my 09. He asked how many miles... I said 16,000 or so. He said the coolant doesn't need to be changed till the 5th year with the "extended life" coolant ... I appreciate being told that.
He then said that I should have the differential fluid changed now though. He said this is recommended for Vettes at this mileage. Anybody out there know as to whether this is a factual comment?
He then said that I should have the differential fluid changed now though. He said this is recommended for Vettes at this mileage. Anybody out there know as to whether this is a factual comment?
Tech Contributor
Joined: Oct 1999
Posts: 41,036
Likes: 9,798
From: Charlotte, NC (formerly Endicott, NY)
It isn't required at your or any other mileage unless you have been doing track events and then it should be changed after 24 hours of track use. Read your Owners Manual, it is all explained in the manual. Pages 6-4 and Page 4-14 lower right.
Bill
Bill
Melting Slicks
Joined: Dec 2006
Posts: 2,694
Likes: 106
I like to replace ALL fluids in new cars relatively early, to dispose of break-in excess crap from metal shavings to internal contamination. I don't do it as early as some here (100, 200, 500 and 1K miles the norm), but consider 3,000 miles a good number, and that's when I plan to replace engine, transmission and differential fluids. Tranny does not have a synthetic lubricant, so will switch to that (probably RP). Engine same M1 5/30 as the factory, and OEM differential fluid (it's synthetic). If you haven't changed them before, or don't know if previous owner did, I'd do all 3. And don't forget brake fluid every 2 years. And clutch is a royal b*tch, so many of us replace the fluid in the reservoir when it gets dirty. Mine was dirty even with only 10 miles, and have changed it 4 times in 1K miles, and will continue to do so until it no longer becomes dirty as easy. I personally don't believe it's a solution, but I tried bleeding it properly, and quickly ditched the project. By doing this reservoir swap since day 1, I should be okay with this method alone. I hope 
. Good luck.
. Good luck.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
While GM has no specific maintenance schedule for changing differential fluid, it's left up to the individual to do what makes sense to them. Generally speaking, most people don't drive their cars hard enough to warrant ever changing the fluid. Some people tend to go overboard the other direction and change it early and often. Places that profit will nearly always tell you it needs changed any time you get your car serviced.
Even though differential gears need the longest break-in period and generate the highest particle count of any lubricated car part, they also survive the longest without maintenance. The endurance testing has shown that differential failure due to lubrication issues on the factory fill is non-existent. That's why there's no maintenance schedule.
The bottom line is, do what makes you comfortable. If you do change it, at least use the GM fluid that has the correct amount of modifiers to match the engineering design of the parts being lubricated.
Even though differential gears need the longest break-in period and generate the highest particle count of any lubricated car part, they also survive the longest without maintenance. The endurance testing has shown that differential failure due to lubrication issues on the factory fill is non-existent. That's why there's no maintenance schedule.
The bottom line is, do what makes you comfortable. If you do change it, at least use the GM fluid that has the correct amount of modifiers to match the engineering design of the parts being lubricated.
Racer
Joined: Feb 2012
Posts: 258
Likes: 0
From: Ponte Vedra Florida
I had mine changed for free by the dealer. TSB on the fluid if you get popping, binding. Free is good and using the right fluid is also good. My car is a 2008 with only 4K miles, my vette was built in November of 2007, so I will be changing my coolant next month at around 5K miles, 4 months before its 5 year birthday. I understand it is important to change the coolant before the 5 year deadline. I would not of changed the rear diff if I did not have the popping in slow turns first thing in the morning. If you drive the vette hard then I would do the transmission fluid at half the recommended interval.
