CharliB

Looking to replace the rear gear lube with Redline 75W90 or 75W140. Would like some input if anybody has done this. Tried a search but info was old. I have a 2013 A6/C7 3.0T.

porksoda

I don't know if i would change the differential oil so soon. From previous vehicles i have owned they have usually recommended it done at 62K.

CharliB

I have 45,000 miles and have developed a louder than normal whine in rear diff. There was always a slight whine between approx. 44 and 54 mph. It was tolerable but not anymore, even with radio turned up. Has been verified by the dealer and my local indie vw,, audi repair shop. I have CPO but dealer says not a warranty item but a maintenance item. I suggested we change the diff fluid and he agreed to do it but not under warranty. They want to charge me somewhere around $300!

porksoda

Ahhh.

Just as a comparison I got my 5 series differential oil changed/flushed for $80 cdn dollars in 2009. I used LIQUI MOLY fully-synthetic GL 5 SAE 75W-140 LS hypoid gear oil.

I would ask a local indie for pricing on it... $300 sounds a lot unless there are some specific procedures that need to be done for the C7

ByByBMW

Amsoil recommends 75W-90 Synthetic Long Life Gear Lube for both front and rear diffs. Hardest part would probably be finding a dealer.

the_duke

The dealership should be able to tell you what oil you should use. Not sure if it's even an option on your car but do you have the "sport differential"?

But really if it's making a louder than normal noise and your car is still under warranty then they need to make the noise stop. Don't look at it as a fluid change, look at it as a noise your car is making while still under warranty. If anything else was making a not normal noise they would have to fix it. I would tell them to fix the noise.

dshahs420

I have changed all the fluids[except transfer case] in my car to Royal Purple. The transmission got Royal Purple Max ATF and the front and rear diff got Royal Purple Max Gear 75w90. Absolutely love it. The car feels more nimble and lighter on its feet.

tenspeed

Exactly. It's a 2013 and still should be under the original warranty. Fix the problem - don't mask the symptom.

jr'sAudiA6

I recently had all 3 differential gear oils replaced and the transmission fluid replaced at a mileage of about 65K. I have driven over a dozen track events plus a fair amount of spirited driving in between. I did not have any noise from rear diff and transmission was working just fine. Did this out of an abundance of caution. I guess my point is if your rear diff is making a whining noise it is probably not related to the gear oil but something in the diff has warn or failing prematurely. You have 45K miles so are clearly under the original power train warranty. So I would push to have the dealer address the noise under warranty. If they refuse then contact AOA immediately.

AUDIR8FG

Hello
I own an audi R8 V10 year 2012 Im planning to change the gear/transmission oil to the Royal Purple Max Gear but many people saying that is not a proper oil.... can you help?
Thanks a lot