2017 C7 Corvette differential woes…

[Anthony]

2 weeks ago I purchased a 2017 C7 Corvette. Manual trans.
I immediately changed the oil, trans and diff fluid. The car had 31,600 miles when I got it.
The diff fill and drain plugs both have magnets which were covered as expected if the diff has never been serviced.

When I initially serviced it I was under the impression you fill til it pours out. That’s 3 quarts. I later found out it only specs 2.5 quarts. I decided to drain some out a couple of days later and the drain magnet was pretty heavy in metal again. It got my attention so after 264 miles I decided to do a full drain and fill again. This is what both magnets looked liked.

The car drives great. No odd noises or anything weird coming from the diff. I’m wondering if this was just a bunch of residual leftover from the factory fill. What are your thoughts?

 

[ArrestMeRedZ]

Not being a real mechanic, take what I say with a grain of salt, but the first time I drain and fill any of my Chevy differentials I always remove the rear cover and clean it out well before replacing the cover and refilling. On some of them I've flushed a lot of crap out. If you can get to the rear cover I'd suggest doing that.

 

[clinebarger]

Continue to remove the fill plug every once in a while & clean the magnet.....Hopefully the metal deposits will trend down.

The magnets are small & load up easily. Without any noise.....I wouldn't condemn anything yet.

 

[clinebarger]

Not being a real mechanic, take what I say with a grain of salt, but the first time I drain and fill any of my Chevy differentials I always remove the rear cover and clean it out well before replacing the cover and refilling. On some of them I've flushed a lot of crap out. If you can get to the rear cover I'd suggest doing that.

Not possible on a Transaxle Corvette.

 

[zfasts03]

For what it is worth...

My `03 Z06 driver side cover was removed twice in low mileage. Only 14,500 on the car now.

Both times was to fix the drivers side axle seal. The first time it was done around 5000 miles under warranty at the dealer.

The second time was repaired by me around 10,000 miles in accordance with updated sealant and procedures according to Paul K. GM Corvette master tech, from in person discussion at Corvette's at Carlisle.

Both times the large magnet (ring) housed in the driver side side cover was full of metal. The first time I figured, okay break in metal. When I saw this the second time, I though maybe something is wrong. Maybe there is, maybe there isn't. Not much I can really do, but drive it, until something starts making noises.

I don't remember if the drain or fill plug is magnetic, I don't think it is on a 5th gen vette.

The amount of metal on your drain plug looks minuscule compared to what I had on the big ring magnet.

My diff. is a 3.42 Getrag. Not sure what the 7th gen uses?

 

[wpod]

Most people do not understand why it is a good thing to change the oil sooner on a new vehicle if you plan to keep it for a long time.

 

[Greasymechtech]

Normal wear and tear, especially when considering break-in

Capacity depends on mLSD or eLSD???

I'd upgrade to a dimple, psr, or gold plug, or equivalent. Catch more! Or, one can say the OE fluid recommendation is nothing to brag about.

The making gears in diffs/transaxles with MIM, PIM, or PM recipes already Grinding back into powder is just fine!

 

[Cujet]

Really, that's not unusual for most differentials. There is a reason the magnet is helpful.

 

[Anthony]

If that oil had a lot of mileage on it I’d think normal too. The thing that concerns me
Is that the oil was only used for 264 miles.

I’ll keep an eye on it for sure.

 

[Anthony]

For what it is worth...

My `03 Z06 driver side cover was removed twice in low mileage. Only 14,500 on the car now.

Both times was to fix the drivers side axle seal. The first time it was done around 5000 miles under warranty at the dealer.

The second time was repaired by me around 10,000 miles in accordance with updated sealant and procedures according to Paul K. GM Corvette master tech, from in person discussion at Corvette's at Carlisle.

Both times the large magnet (ring) housed in the driver side side cover was full of metal. The first time I figured, okay break in metal. When I saw this the second time, I though maybe something is wrong. Maybe there is, maybe there isn't. Not much I can really do, but drive it, until something starts making noises.

I don't remember if the drain or fill plug is magnetic, I don't think it is on a 5th gen vette.

The amount of metal on your drain plug looks minuscule compared to what I had on the big ring magnet.

My diff. is a 3.42 Getrag. Not sure what the 7th gen uses?

For what it is worth...

My `03 Z06 driver side cover was removed twice in low mileage. Only 14,500 on the car now.

Both times was to fix the drivers side axle seal. The first time it was done around 5000 miles under warranty at the dealer.

The second time was repaired by me around 10,000 miles in accordance with updated sealant and procedures according to Paul K. GM Corvette master tech, from in person discussion at Corvette's at Carlisle.

Both times the large magnet (ring) housed in the driver side side cover was full of metal. The first time I figured, okay break in metal. When I saw this the second time, I though maybe something is wrong. Maybe there is, maybe there isn't. Not much I can really do, but drive it, until something starts making noises.

I don't remember if the drain or fill plug is magnetic, I don't think it is on a 5th gen vette.

The amount of metal on your drain plug looks minuscule compared to what I had on the big ring magnet.

My diff. is a 3.42 Getrag. Not sure what the 7th gen uses?

Yes the C7 is also a 3.42 for manual cars. How many miles did you end up putting on yours after the 2nd repair?

 

[zfasts03]

only about another 5000 miles after second repair

 

[4WD]

Not possible on a Transaxle Corvette.

That’s a big difference right there - might pour an extra quart through with both plugs out - not many options

 

[KJH]

I am not familiar with vettes or transaxle stuff, but that doesnt look too bad based on what I've seen from Japanese and German RWD pumpkin diffs. Its not an engine, as long as the gears still mesh it'll work.

Either way, changing the diff fluid every 3 oil changes or every year or so with good quality gear oil is a good idea when it comes to rwd performance stuff IMO, especially if driven hard/at the track. An appropriate size diff for the application can take a lot of abuse if driven normally, but with big tires, big engines and a heavy foot it can become a weak link in the drivetrain system.

Not sure of the science but from my anecdotal observation, heat damage(from what i've guessed, likely from old gear oil) is what weakens them over time to the point were they sometimes go kaboom during a shock load, not so much minor shearing so long as the magnet does its job.

 

[Anthony]

I am not familiar with vettes or transaxle stuff, but that doesnt look too bad based on what I've seen from Japanese and German RWD pumpkin diffs. Its not an engine, as long as the gears still mesh it'll work.

Either way, changing the diff fluid every 3 oil changes or every year or so with good quality gear oil is a good idea when it comes to rwd performance stuff IMO, especially if driven hard/at the track. An appropriate size diff for the application can take a lot of abuse if driven normally, but with big tires, big engines and a heavy foot it can become a weak link in the drivetrain system.

Not sure of the science but from my anecdotal observation, heat damage(from what i've guessed, likely from old gear oil) is what weakens them over time to the point were they sometimes go kaboom during a shock load, not so much minor shearing so long as the magnet does its job.

Yeah I normally change it every 10,000 or so In my Mustang. I plan to do the same here. That amount wouldn’t concern me over a normal interval. The magnets had all of that with only 264 miles of use. So it’s got my attention at the moment.

 

[KJH]

Yeah I normally change it every 10,000 or so In my Mustang. I plan to do the same here. That amount wouldn’t concern me over a normal interval. The magnets had all of that with only 264 miles of use. So it’s got my attention at the moment.

A perhaps far fetched theory I just thought of after re-reading your post is perhaps since you over-filled it, it could have picked up more residual metal bits since it could have been reaching into parts of the diff that fluid previously did not get to statically or flinging around during operation. I have no idea what the vette diff looks like inside to know the likelihood of this, but just a thought. Either way, I would just change it at a good interval and see what it looks like next change.