S'vette

Im a little confused so this may be a dumb question. In a C6 auto is the transmission and differential the same or uses the same fluid? So if I changed my tranny fluid did that also change my diff fluids?

MikeERWNC

NO... it is not the same.
You should do them together when the car is in the air.


Use this, it is easier to get the oil into the car.

Gerdia

great post

AD2VET

No, changing the transmission fluid does not change the differential fluid. They are two separate units.

greenbeauty

When you have no issues..
Do I need to change the differential oil also ?

I've got an 2006 manual, and I don't have any issues.
Also in my 3 years ownership I never refreshed this oil

Do I need to?

veloz

it depends on your driving habits and mileage of the car..

racing/hard driving: once a year or as needed

mileage: around 30K miles, change it

you will be surprised on the color of the fluid and the difference in shifting.

greenbeauty

(car is around 30 miles)

Huh.. Beter shifting?
We are talking about the differential / rear axl oil ? not the transmission oil ..

veloz

oops, should have qualified that...i changed both fluids in my car...you should too...super easy to do...

S'vette

Thanks

greenbeauty

Last year I did the trans fluid...
No big difference..

I was just wondering what the benefit is from changing the rear axl oil when you have no problems at all

waveguerilla

I have a 2009 Z51 and the rear leaf spring is completely on the way of the diff drain plug.

No chance to put an alen wrench. So here is a solution that worked :

Formuhawk99

I have ahumming noise in the rear of the vehicle but it only starts after30 to 45 minutes of continuos driving.
I had the diff fluid changed a few years ago. Should it be changed again or do I have another issue. I have an 09 with a manual and 30k on the clock.

mfoti

Thank you OP. I changed my gear oil with Dexron LS 3 years ago in m7 07 C6 with only 4,000 miles. Didn't fix the severe chattering. I assumed i had to live with it. 3 years later at 9,000 miles it is really, really bad and loud. My last shot at fixing was going with Amsoil Severe gear 75-90. I added an extra shot of the anti-slip additive to the amsoil as recommended by others and voila.. NO MORE Chattering. It is an amazing fix. Not sure why the dexron did not work.

RWGD1900

I changed the gear oil in my 2008 Corvette differential and used the ACDelco DEXRON LS Gear oil 75W-90.
Part number 10-4034 #88862624.
The noise was gone the first time I backed it out of the garage and has been quiet ever since, a real joy to drive now.

940CACC

did the same thing last week and not a sound out of it since the swap...this stuff works

SCcues

Thanks to the OP and everyone for such a great informative thread. I've learned so much about my car since I joined this Forum.......

Red08

I changed the diff fluid on my '08 a couple of months ago as preventative maintenence, not because of any noise, chatter etc. It was a very simple DIY project. To get the oil back into the diff, I have a a pump that is actually desinged to fit on a quart bottle for adding gear oil to the lower unit of outboard motors. I really worked nice, and got 99% of the oil out of the quart container.

vette6500

Just changed my diff fluid today for the 3rd time on my 2005 Z51.

With the rear leaf spring in the way of the drain plug, I've used medium length ballhex socket the last 2 times, rounding out the hex hole more each time (I switched the drain and fill plug before to get a fresher hex hole to the drain side, but it was rounded off quite a bit last time).

I didn't think I could get it off today, but barely got it off rounding off more of the hex hole...

I tried to get 2 new replacement since these probably cannot remove next time, but dealership parts was closed for the weekend.

So I checked out Autozone to no avail, but did find a suitable replacement plug at Pepboys (engine oil drain plug)!!!
Even better than being an identical replacement, this has a 17mm head on it.
Hand tightened, then final tightened with a regular 17mm wrench. Can't fit the 17mm fully on it, but even at the ~30 degree angle to clear the lower subframe, I could easily tightened it as much as I wanted with no chance of rounding off anything.

Just wanted to put this replacement option in this thread for 2005 owners to consider using if/when they get the drain plug off.

I bought 2 and used for both drain and fill plug, since both of my plugs have rounded off holes.

Oh, I reused the washer/seal from the OEM plug (just pull off and push onto new plug), since the new plug came with an iffy looking fiber looking washer.

Cost was $4.50 X 2 + tax = less than $10.
Now I can change diff fluids whenever I want without worries

Z51vette88

So let me get this straight. You dont need to add limited slip additive anymore?! With fluide 88862624. An does the z51 package take more than the regular base? By the sounds of it no

Thanks

PJZVET

Just checking back in....1 year later and still no problems