mike123460

So backstory first.

I took my 650whp A8 z06 to the track and broke the rear differential, got it replaced under warranty, and I want to make sure it doesn't happen again.

Got around 500 miles on the new OEM rear differential, should I have them replace the fluid for ~200$ or is it just a waste of money?

Thanks,
Mike

jswatek

Why not do the recommended maintenance? It is really pretty easy to DIY.

Paul R

Definitely worth it as it is so simple to do and removes the assembly lube and small metal particles that result from break-in. If possible, you can save some money and do it yourself. It is easy...open fill plug, open drain plug, drain, close drain plug, fill, replace fill plug.

rbarta

Yes, you will have metal shavings in the diff on initial break in. Mine did. Easy job. Mine didn't cost that much at Tony's Corvette in MD.

Wulverine

Waste of money.

Does Chevy "break" in every differential and change the fluid before selling every car and truck?

HorsePowerObsessed

The stock fill fluid is NASTY. I would DEFINITELY change it. The 3 quarts of differential fluid you have to buy end up costing roughly 45 bucks and you can easily do it yourself.

mike123460

No but do you expect them to hold the same level of quality and workmanship as us? I've seen a lot of rear diffs fail lately...

Warp Factor

Did the failures have anything to do with lubrication failure?

Hollingswerth

I just did mine at 2500 miles. Old fluid had a noticeable amount of fine metal particles in it, and the magnetic drain plug had a little over an 1/8" of metallic sludge on it. I didn't save and measure the old fluid to see if it had been underfilled, as some report.

Used a 3/8" flex head ratchet. Overall easy job, except for initially getting the ratchet into the fill plug, and a bit messy trying to get the fill plug screwed back in with oil running out the hole down my hand & arm.

Plan to keep my car for a long time...cheap insurance in my mind. Plus, I know it is properly filled and torqued.

thebishman

What is wrong with some of you guys? This is incredibly cheap insurance to try and prolong the life of and enhance the function of the rear diff. Why in the hell wouldn't you have this done, even if you never intend to track the car?

Bish

Newton06

^^^This.

Noticeable difference after swapping for high-quality synthetic. Even changing the good stuff after heavy track use as part of regular maintenance made a difference.

If your car is a DD or cars & coffee/garage queen variant, it's probably fine to stick with the factory maintenance schedule.

But I look at it like buying your SO flowers every now and again. Is it absolutely necessary? In most cases no. But it sure as hell never hurts!

383vett

Sounds like you may have overfilled your differential. The oil should be filled to the bottom of the fill plug. It houldnt be running out the hole.

badhabit_wb

What Bish said!

FYREANT

As many have said, yea, I'd do it. Its cheap, and easy to do yourself. There is a guide in the How To sticky thread in C7 general

BadC7

If you want I can show you what mine looks like. Maybe I should have changed out the oil.

Checkmate1

Anyone do a DIY on this?

What synthetic fluid is everyone using and is 3 Qts exactly what is needed?

robertbruce

Mine was filthy and a quart low when I did it.

VegasC7Z06

https://www.corvetteforum.com/forums/c7-tech-performance/3800362-diy-manual-transmission-and-rear-differential-fluid-service.html

3 qt gm fluid.

Bill Dearborn

I agree. A lot of diffs go 50 to 100 thousand miles without ever having the fluid changed. Dropping the throttle and dumping the clutch at the strip applies a lot of force and can break a transmission that has a weak/fatigued part in it. Changing the fluid will do nothing to prevent that. The fluid is nasty the day it is put in the diff so the fact it is nasty at some time after isn't an indicator of anything. Fluid reduces wear on the gears and bearings in the diff and doesn't really affect whether or not a part has an unseen manufacturing flaw or has been abused to the point it has fatigued due to multiple launches.

Bill

cvp33

After mine went through it's break in period we replaced ALL the fluids:

Transmission - Castrol ATF+4 full synthetic
Rear Diff - Mobil1 Delvac synthetic with friction modifier
Oil - 0w50 Mobil1 full synthetic
Brake - Castrol SRF