C6 Rear diff fluid update?
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 38
Likes: 11
From: Fort Pierce, Florida
C6 Rear diff fluid update?
Ill be doing a diff fluid change soon and Ive read all the many many thread about it. They all say to use the GM Ls Gear Oil which has the friction modifier already in it. I will probably go this route.
However I did also find this thread https://www.corvetteforum.com/forums...id-change.html in which apparently GM again has updated their recommendations; the OP of this thread learned of it from his local dealership. This time they reccomend using GM synth gear oil with an additive. This is the only thread Ive seen that mentions this new TSB. Does anybody have this tsb or know anything about it. The thread is from 2016, and if you read through a member does indeed find the tsb and GMs new recommendation about sy thetic gear oil + additive.
However I did also find this thread https://www.corvetteforum.com/forums...id-change.html in which apparently GM again has updated their recommendations; the OP of this thread learned of it from his local dealership. This time they reccomend using GM synth gear oil with an additive. This is the only thread Ive seen that mentions this new TSB. Does anybody have this tsb or know anything about it. The thread is from 2016, and if you read through a member does indeed find the tsb and GMs new recommendation about sy thetic gear oil + additive.
Last edited by PrecisionVette; Nov 26, 2018 at 10:38 AM. Reason: Spelling
Burning Brakes
Joined: Jan 2017
Posts: 1,122
Likes: 199
From: TX
The "new" Synthetic doesn't look like it is for the Corvette.
It does NOT contain the required friction modifier for the LSD, although it could probably be added. And it's grape scented??
Stick with the AC Delco Dexron Part# 88862624.
It does NOT contain the required friction modifier for the LSD, although it could probably be added. And it's grape scented??
Stick with the AC Delco Dexron Part# 88862624.
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 38
Likes: 11
From: Fort Pierce, Florida
Yes I already decided I would. Thanks for your quick reply. My question is about the update mentioned in the above thread. The TSB that changes the recommendation to synth+ modifier; does it exist or what? Several members in that thread seemed to confirm it and the OP's local dealership gave him the part no for the synthetic stuff back in 2016. Where can I find that TSB? Is it legit? And if it is legit just wondering why would we ignore this TSB and not the one from 2007 or 2008? Just asking because the general consensus about it on this site seems to have not changed since then.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
https://www.corvetteactioncenter.com...6-corvettes/6/
I don't find any TSB regarding a different fluid for C6 differentials after the Dexron LS one. If the "new" one was written in 2016 or anytime thereabouts, it may pertain to the C7's only.
The TSB for Dexron LS was first published 01-09-2008 even though the new fluid had been the factory fill for a few months prior. Best estimates were the change came sometime in Sept or Oct of '07
The only reason the TSB stated to drive 8-10 tight figure 8's to work the fluid into the clutches, was so the customer would not continue to experience the clunk/chatter when leaving the dealership until he/she drove it for a while. i.e. aka instant customer satisfaction.
My '08 came off the line 10-30-07 and already had the Dexron LS. It was changed at 55K miles under warranty (axle seal leaks) and again by me at 98K (no figure 8's). I'm at 154K now and don't plan on another change for at least another 50K if at all. If you already have Dexron LS and you have less than 150K miles, I wouldn't bother changing it until at least then.
I don't find any TSB regarding a different fluid for C6 differentials after the Dexron LS one. If the "new" one was written in 2016 or anytime thereabouts, it may pertain to the C7's only.
The TSB for Dexron LS was first published 01-09-2008 even though the new fluid had been the factory fill for a few months prior. Best estimates were the change came sometime in Sept or Oct of '07
The only reason the TSB stated to drive 8-10 tight figure 8's to work the fluid into the clutches, was so the customer would not continue to experience the clunk/chatter when leaving the dealership until he/she drove it for a while. i.e. aka instant customer satisfaction.
My '08 came off the line 10-30-07 and already had the Dexron LS. It was changed at 55K miles under warranty (axle seal leaks) and again by me at 98K (no figure 8's). I'm at 154K now and don't plan on another change for at least another 50K if at all. If you already have Dexron LS and you have less than 150K miles, I wouldn't bother changing it until at least then.
Drifting
Joined: Apr 2013
Posts: 1,501
Likes: 185
From: Erie PA
i was having the "clunky" sound when turning and going slow. came to the forum and read, and read, and read. There are a few different oils that were recommended but it was strongly suggested that I get the specific GM oil from the dealer , but it was more expensive. I went with Mobil 1 alternative that a few people mentioned to save a few bucks. It made the noise a bit less, but was still there and very annoying. So, i went to the dealer and bought the expensive oil and tried again. Instantly fixed the issue and no problem since. live and learn. As mentioned above "Stick with the AC Delco Dexron Part# 88862624."
Melting Slicks
Joined: Feb 2016
Posts: 2,984
Likes: 380
From: Edmond Oklahoma
Ill be doing a diff fluid change soon and Ive read all the many many thread about it. They all say to use the GM Ls Gear Oil which has the friction modifier already in it. I will probably go this route.
However I did also find this thread https://www.corvetteforum.com/forums...id-change.html in which apparently GM again has updated their recommendations; the OP of this thread learned of it from his local dealership. This time they reccomend using GM synth gear oil with an additive. This is the only thread Ive seen that mentions this new TSB. Does anybody have this tsb or know anything about it. The thread is from 2016, and if you read through a member does indeed find the tsb and GMs new recommendation about sy thetic gear oil + additive.
However I did also find this thread https://www.corvetteforum.com/forums...id-change.html in which apparently GM again has updated their recommendations; the OP of this thread learned of it from his local dealership. This time they reccomend using GM synth gear oil with an additive. This is the only thread Ive seen that mentions this new TSB. Does anybody have this tsb or know anything about it. The thread is from 2016, and if you read through a member does indeed find the tsb and GMs new recommendation about sy thetic gear oil + additive.
some here have a copy of a service bulletin than calls for a new fill and no additives.
Last edited by LowRyter; Nov 26, 2018 at 07:38 PM.
Drifting
Joined: Apr 2013
Posts: 1,501
Likes: 185
From: Erie PA
I was going to try that route as well, but I had a road trip planned with my son from Pa. to Deal's Gap two days later and wanted to get the issue resolved ASAP..... so I sucked it up and paid $28 per quart at the local stealer.
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Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
No, read your manual. My manual says to use GM additive along with the specified gear lube. In my case, it took two bottles of GM additive, the second bottle only required a couple of ounces. for my case, for a few bucks, it took the click out of the rear end.
some here have a copy of a service bulletin than calls for a new fill and no additives.
some here have a copy of a service bulletin than calls for a new fill and no additives.
Melting Slicks
Joined: Feb 2016
Posts: 2,984
Likes: 380
From: Edmond Oklahoma
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 38
Likes: 11
From: Fort Pierce, Florida
No, read your manual. My manual says to use GM additive along with the specified gear lube. In my case, it took two bottles of GM additive, the second bottle only required a couple of ounces. for my case, for a few bucks, it took the click out of the rear end.
some here have a copy of a service bulletin than calls for a new fill and no additives.
some here have a copy of a service bulletin than calls for a new fill and no additives.
Last edited by PrecisionVette; Nov 27, 2018 at 07:05 AM.