HGperformance

- 2015 Z06 M7* - 8800 miles
After seeing many people state that the Differential has been under filled from the factory and fluid coming out looking nasty and people needing to replace diff's i was not gonna standby and let it happen to my vehicle so on Wednesday i decided to do my own drain and fill and the results shocked almost everybody in the shop. Here are my personal notes.
- Racked car up and started the drain and fill process.

- Both drain and fill plugs hand tight loose...

- Removed drain plugs found that plastic gaskets were used causing a seep in the rear diff, also found gunky fluid mixed with metal shavings on plug.

- Started drain process, Fluid came out pitch dark and silver and thick as can be... almost milkshake like and metal particles can clearly been seen.

- At this point everyone in the shop stops what they are doing and just stare at what is coming out of the diff in absolute awe.

- Grab a video and pictures of the plug and fluid coming out and capture some fluid in a cup for evidence.....

- At this point i fill with new fluid and replace plastic gasket with proper metal and plan on doing another drain and fill in a 1000 miles to remove anything else that is left behind

Let me just say that even with break in additives i DO NOT believe that fluid of any kind should EVER look like that, I am absolutely appalled and disgusted with GM that they have the audacity to sell us these 110K cars with this type of problem right out of the factory. I called the Chevy dealer i take the vehicle for warranty work and had the service manager note and file my concern so i am covered in the future but still my god....
PLEASE change out the diff fluid and save your investment!

jswatek

M8?

capevettes

I agree the rear diff fluid should be checked and changed. I just did my 2016 M7 at abut 4,000 miles. However, I was pleasantly surprised that the plugs were tight, the fluid was where it should be and didn't look bad at all when I drained it.

AZDANZ06

I had mine done at 2K miles, the mechanics said it looked nasty. The dealership did not charge me for the labor as I brought my own GM Diff Fluid.

jswatek

Thanks for the heads up! My M7 coming up on 2k.

Quechee 45

did mine, 2015 Z06 M7, at 1000 miles and it was nasty. After drain then fill and with plug in ran car in gear (rear wheels in the air) at 1000 rpm for 2 to 3 minutes and then re checked diff and added a small amount of fluid.
Getting my 2017 Z06 M7 end of next week and will do the same.

mdz06vetter

thought once upon a time there was a TSB that indicated the dealer was to check and service the diff as part of the PDI??????

mdz06vetter

thought once upon a time there was a TSB that indicated the dealer was to check and service the diff as part of the PDI?????? which we all know the dealers really pay attention to! WINK! WINK!

djnice

My fill and drain plugs in the 17 GS were hand tight too. It was at the correct level.

dar02081961

Milky and thick? With no major leaks. That means there was possibly water in the fluid or in the eLSD when it was originally filled?

Problem I am having with this is the eLSD calls for ATF Dexron VI and though I am not 100% sure I don't think Dex VI turns milky or silver when exposed to water. And it certainly isn't thick and doesn't get thicker when exposed to water.

So sitting a thousand miles away in my arm chair rocker I would say someone filled this eLSD with the wrong fluid. A condition that is extremely unlikely to happen at the plant or at the eLSD manufacturing facility.


Please post the video or the photos. Dex VI will be obvious contaminated or not.

C7/Z06 Man

The eLSD (clutch pack) and the rear end gear fluid are located in separate compartments and the elsd takes transmission fluid so IMHO it would be very hard to get the two mixed up.

BOBSZ06

Mine looked fine...chocolate brown...nothing out of order for 8000 miles.

Z06NJ

I know I should RT(F)M, but when does the manual say you should replace this fluid anyway?!
(Mine is a manual)

mdz06vetter

rear end and transmission fluid changes are both recommended at every 45000 miles, but that is really dependent on how you use your vehicle. Again, moisture is the biggest danger for our cars, and unless you are in a temperature controlled environment you are risking moisture seepage into all your fluids. Thus I think most mechanics would recommend changing fluids every 2-years as a practice.

08G8V8

If you track your car it says to drain and refill after the first track day, then every 24 hours of track time after that.

Bad Dad

I love my Vette I'm a nut I changed it at 200 miles but had checked it when I got her home, changed again at 700 then at 1200 and will do it again at 2500. My problem is I want to change my trans fluid and cant get step by step instructions Love taking care of this car so I know its done right and often.

pnoman

Just changed mine at 500 miles, drain and fill plug not very tight but fluid looked fine.

lordofwar

didn't have to change fluid,just had a new rear end installed at 500 miles.

C7/Z06 Man

What happen?

lordofwar

bad rear end.was a bunch of them.whine at 30 to 40 mph.A8