Diff. lube
 

I believe my 2005 C6 Vett has AC Delco synthetic oil in the Differential. I have been told to use only AC Delco Dexron LS Gear Oil 10-4034. Is this oil a synthetic oil and if not will it harm the differential that had synthetic in it before. Hearing lots of clunks coming from the Diff. and want to change the oil. Thanks.

Different lube change
 

Just changed mine in my 08. Used Redline 75-90 a full synthetic with the limited slip additive in it.No noise or chatter. Spoke with Redline and they told me no additive is necessary with their gear oil. Got it at Summit Racing.

I just did mine also, used GM fluid. I've heard Red Line a good product also: Read More here:https://www.corvetteforum.com/forums...-specific.html

There is lots of good info regarding this subject.

DEXRON LS has been corvette factory fill since MY2009 and is fully synthetic with limited slip additive already in it. It is far superior to the Mr Goodwrench factory fill for the 2005 thru 2008 model years. DEXRON LS is definitely recommended by GM for the early year C6s vettes that suffer from diff clutch chatter. There is definitely no problem with you using it in your 2005.

Thanks for the info. Hope that solves my problem.

Last month I had my 05 have it's 50,000 miles check-up including Diff and Trans fluid change at the Dealership, so I hope they would use proper fluid, they should know what to use.

i am new to this. Why change it out?

The early C6 vettes (MY2005 thru 2008) were prone to rear differential clutch chatter due to the poor formulation of the factory gear lube. The GM solution finally arrived with the introduction of DEXRON LS diff fluid as factory fill for MY2009. There are long time corvette owners who will tell you that diff clutch chatter has been a problem even for older generation corvettes prior to the C6. Prior to DEXRON LS, many have stopped chatter with aftermarket fluids manufacturered by AMSOIL, Redline, RP, etc.