Differential change
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
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I couldn't find anything in the owner's manual but this.
Rear Axle
When to Check Lubricant
It is not necessary to regularly check rear axle fluid unless a leak is suspected or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired.
I'd say 100,000 is a fair guess to check the fluid level and maybe change it?
Elmer
Rear Axle
When to Check Lubricant
It is not necessary to regularly check rear axle fluid unless a leak is suspected or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired.
I'd say 100,000 is a fair guess to check the fluid level and maybe change it?
Elmer
Burning Brakes
Joined: May 2008
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From: Aledo, TX
I would change the fluid for sure, it is not a bad idea to change the fluid shortly after break in for the diff and the tranny (manual). I plan on changing all my fluids after 500 miles.
If your tracking the car you should change it after every season or sooner. Fluids are much cheaper than the alternative.
If your tracking the car you should change it after every season or sooner. Fluids are much cheaper than the alternative.
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St. Jude Donor '12 thru '17
Unless you track it hard there's no reason to change the diff oil until at least 50k miles. Doing it at 500 miles can't hurt anything but is a total waste of money.
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I change out the differential fluid by at least the first 1,000 miles in every vehicle I own. There is usually quite a bit of wear that occurs during break-in which means material ends up in the fluid. However the only place I have seen the early change required by GM is for the rear differential of the HD pickups which do require (at least for my 2001 and 2006) the fluid to be drained and replaced after initial break-in mileage and again after the first heavy towing.
It is probably OK to leave in but I prefer to get the particles that result from early break-in operation out of there.
It is probably OK to leave in but I prefer to get the particles that result from early break-in operation out of there.
Drifting
Joined: Apr 2011
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From: Houston, Tx
St. Jude Donor '11-'12-'13-'14
I change out the differential fluid by at least the first 1,000 miles in every vehicle I own. There is usually quite a bit of wear that occurs during break-in which means material ends up in the fluid. However the only place I have seen the early change required by GM is for the rear differential of the HD pickups which do require (at least for my 2001 and 2006) the fluid to be drained and replaced after initial break-in mileage and again after the first heavy towing.
It is probably OK to leave in but I prefer to get the particles that result from early break-in operation out of there.
It is probably OK to leave in but I prefer to get the particles that result from early break-in operation out of there.
look at the old oil in the sun and you will be glad you changed it.
Burning Brakes
Joined: May 2008
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From: Aledo, TX
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St. Jude Donor '12 thru '17
Careful with your "ignorant" comments, unless you want to have a detailed discussion about differential gear install, setup, break in, etc. You'll lose.
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Yup. Particularly since I've built a lot of different differentials and installed a lot of gears. Just because you think you can see something doesn't mean there's a problem with the oil. If that were the case GM and all other manufacturers would recommend diff oil changes after break in, which none do.
Careful with your "ignorant" comments, unless you want to have a detailed discussion about differential gear install, setup, break in, etc. You'll lose.
Careful with your "ignorant" comments, unless you want to have a detailed discussion about differential gear install, setup, break in, etc. You'll lose.
My C6 had noisy chattering clutch plates. I changed the oil out (recommended by GM) to Amzoil, or the like, and fixed the problem. Otherwise, I would not have touched the rear. Since the oil change, I haven't done squat to the differential.
Elmer
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I have no skin in the game, but just for information I'll let you know I owned my street driven '97 C5 2:73 equipped A4 for 17 years and 62k miles, and never once changed the fluid. As far as I know nothing says there is a problem with micro sized particles present in the fluid of a lubricated device given the clearance dimensions between metal components. I might add, the differential never made a whine or sprung a leak either, unlike a lot of other C5s of that era.
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St. Jude Donor '12 thru '17
For a little clarification, here are the key differences between an engine and a differential as far as oil contamination, clearances and oil change frequencies.
In an engine there are a lot of journal bearings with very close tolerances. There is also fuel and exhaust gases in an engine that can chemically contaminate the oil. Chemical contaminates and/or particles can destroy the soft surface of a journal bearing, thus the frequent oil change interval.
A differential has roller bearings, not journal bearings. The tolerance on roller bearings is much looser than a journal bearing, and there is no soft surface in a roller bearing, they are incredibly hard. The tolerance between the ring and pinion gear is very loose (much looser than most people would expect). There is no fuel or exhaust gas in a differential to chemically contaminate the oil.
The break in period for new gears in a differential is very short. There is no break in period for the roller bearings. That's why there is no mention of any break in procedure for differentials from any auto manufacturer. While changing the diff oil after some perceived break in period on a new car won't hurt anything, it's not needed, isn't helping anything, and is a complete waste of money and resources.
In an engine there are a lot of journal bearings with very close tolerances. There is also fuel and exhaust gases in an engine that can chemically contaminate the oil. Chemical contaminates and/or particles can destroy the soft surface of a journal bearing, thus the frequent oil change interval.
A differential has roller bearings, not journal bearings. The tolerance on roller bearings is much looser than a journal bearing, and there is no soft surface in a roller bearing, they are incredibly hard. The tolerance between the ring and pinion gear is very loose (much looser than most people would expect). There is no fuel or exhaust gas in a differential to chemically contaminate the oil.
The break in period for new gears in a differential is very short. There is no break in period for the roller bearings. That's why there is no mention of any break in procedure for differentials from any auto manufacturer. While changing the diff oil after some perceived break in period on a new car won't hurt anything, it's not needed, isn't helping anything, and is a complete waste of money and resources.
Burning Brakes
Joined: Dec 2003
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From: Boca Raton Florida
On my previous 2 C6's that I owned , I changed the rear end fluid because the first one had chatter and was replaced under warranty . The second one I bought used and had 25k miles and I did it just for the heck of it . This vehicle I am not going to do anything . Also , I used to change my oil the first 1k miles and I am also going to wait until the OLM tells me to do so . I am jumping off the way too much maintenance bus , but that's just me . Do what makes you feel good and enjoy your car ..... 
Race Director
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From: Texas Hill Country
this is not a correct statement. there are manufacturers, like Mercedes benz AMG products, that require a differential service early in the cars life (1000 miles). as mentioned, chevy trucks have an early diff service. BMW M series cars require a 1200 mile diff service. there are others.....
Tech Contributor
Joined: Aug 1999
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From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
For a little clarification, here are the key differences between an engine and a differential as far as oil contamination, clearances and oil change frequencies.
In an engine there are a lot of journal bearings with very close tolerances. There is also fuel and exhaust gases in an engine that can chemically contaminate the oil. Chemical contaminates and/or particles can destroy the soft surface of a journal bearing, thus the frequent oil change interval.
A differential has roller bearings, not journal bearings. The tolerance on roller bearings is much looser than a journal bearing, and there is no soft surface in a roller bearing, they are incredibly hard. The tolerance between the ring and pinion gear is very loose (much looser than most people would expect). There is no fuel or exhaust gas in a differential to chemically contaminate the oil.
The break in period for new gears in a differential is very short. There is no break in period for the roller bearings. That's why there is no mention of any break in procedure for differentials from any auto manufacturer. While changing the diff oil after some perceived break in period on a new car won't hurt anything, it's not needed, isn't helping anything, and is a complete waste of money and resources.
In an engine there are a lot of journal bearings with very close tolerances. There is also fuel and exhaust gases in an engine that can chemically contaminate the oil. Chemical contaminates and/or particles can destroy the soft surface of a journal bearing, thus the frequent oil change interval.
A differential has roller bearings, not journal bearings. The tolerance on roller bearings is much looser than a journal bearing, and there is no soft surface in a roller bearing, they are incredibly hard. The tolerance between the ring and pinion gear is very loose (much looser than most people would expect). There is no fuel or exhaust gas in a differential to chemically contaminate the oil.
The break in period for new gears in a differential is very short. There is no break in period for the roller bearings. That's why there is no mention of any break in procedure for differentials from any auto manufacturer. While changing the diff oil after some perceived break in period on a new car won't hurt anything, it's not needed, isn't helping anything, and is a complete waste of money and resources.
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St. Jude Donor '11-'12-'13, '16-'17-'18
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this is not a correct statement. there are manufacturers, like Mercedes benz AMG products, that require a differential service early in the cars life (1000 miles). as mentioned, chevy trucks have an early diff service. BMW M series cars require a 1200 mile diff service. there are others.....
Team Owner
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St. Jude Donor '12 thru '17
If drained lubricants, especially engine oil, looked "clean" it would be an indication that it wasn't doing its job. The only real way to tell if a lubricant is still good is testing, not looking at it.
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St. Jude Donor '11-'12-'13, '16-'17-'18
That is an ignorant answer, have you ever seen what comes out of new Dif after break in?
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From: S.W. Ohio. . . . . . NRA Life Member
ya' mean there's still people around who get fooled by those oil-change places where they compare new tranny/diff/power-steering fluid to a sample they just took from your vehicle?
Of course it will change color and consistancy - during the time it's working properly.