Just over 3 weeks ago, I brought my ’07 3LT M6 Z51 to my local dealer to have all the fluids changed. They changed the Oil & Filter and replaced the Transmission & Differential fluids. I didn’t really have the time to do it myself and I didn’t want to wait so bringing it to the dealer made sense. I now regret that decision but hindsight is 20/20.

Anyway, the dealer ended up putting Dexron VI (P/N 88861954) in my Z51 Manual transmission. When I drove it away I had no idea that was the wrong fluid. Shortly after the fluid was replaced, I started noticing the transmission is clunking and growling at low speeds and turning. I knew something was wrong and that it started happening after the dealer changed the fluids. I brought it back to them and questioned the use of Dexron VI in my transmission but they told me it was okay, handed me TSB #04-07-30-037E and sent me on my way. They said this TSB states that Dexron VI replaces Dexron III (my transmission is labeled Dexron III only) so my transmission has the correct fluid in it.

Well when I read the TSB it clearly states that the TSB does not apply to manual transmissions and that the correct fluid is P/N 88861800. I called the dealer and told them what the TSB states and they agreed to replace the Dexron VI fluid with the correct fluid P/N 88861800 free of charge. They did this on Tuesday (8/6) but unfortunately the issues haven’t gone away. The clunking reduced but the growling is still there and happens very frequently.

My question to the transmission experts on this forum is what kind of damage can be caused by using Dexron VI in a manual transmission for 3 weeks and 300 miles? I know my transmission was not making these noises before the dealer error but I also know they will be reluctant to fix it. I would like to have as much information as possible when I notify the dealer that the correct fluid did not fix the problem.

Thanks in advance – Paul

 

The noise you describe sounds like the differential, not the transmission. What fluid did they use? You want 88862624, which is the latest-greatest, do-not-add-LS-additive lube.

 

I have to agree with the noise coming from the diff, no way that the transmission would be affected by turning.

BJK

 

I originally thought the same thing but they showed me the bottle and it said it contained the LS additive. The dealer P/N is X89021677.

Also the Corvette tech that drove the car said it wasn't the clutch plates sticking and I feel the vibration in the shifter. The clunking and growling doesn't only happen when turning it is just that most of time time when I'm going that slow I'm turning into a parking space, street, etc... but it will happen when I'm going slow and straight too.

 

I also removed, re-torqued and lock-tited my axle nuts because I read that that could cause a clunking noise. They were both fine.

 

89021677 is the old stuff that required addition of limited-slip additive 1052358 as per TSB 07-04-20-002.

That was superseded by TSB 07-04-20-002A that recommends 88862624 and no limited-slip additive.

 

I was told by a different dealer today that since P/N 89021677 is synthetic that it doesn't need the LS additive. At this point, I do not what is right anymore but I'll have the dealer follow TSB 07-04-20-002A which they didn't do originally.

I still want to understand if using Dexron VI in my manual Transmission for 3 weeks and 300 miles will cause any damage. Can anyone provide any insight in to that question?

-Paul

 

This is the correct info...the fluid is called DEXRON LS on the label and is fairly expensive. It specifically requires NO slip additive.

 

That is wrong on two counts. 677 did need the additive, and it is not the current recommended fluid.

 

I do not believe that using Dex VI for a few hundred miles would permanently harm the trans but it is certainly the wrong fluid for the application. It has a different friction spec and so will alter the way the synchro rings operate. They depend on a certain amount of friction in order to do their job. This is why they put a small label on the trans right near the fill and drain plugs that says Dex III only.
I had good luck replacing my trans fluid at 50K with Mobil 1 Synthetic Trans fluid, which says Dex III compatible on the bottle and does not reference Dex VI. I would suggest a refill with this to get all the Dex VI friction modifiers out of your trans. Also, the trans will not be affected by turning. If turning has any effect whatsoever on these strange noises, it is not within the trans, it is in the rear axle. The dealer screwed up and put the wrong fluid into both units...which is amazing.

I had the growling from my axle a few years ago...only first thing when it was cold backing out of the driveway and turning to avoid scraping. Dealer replaced fluid with the Dexron LS and problem solved and has not come back.

 

As mentioned above, any damage with those few miles would have been to the synchros. If you didn't experience any grinding, then no worries. Having said that, many of these TR6060 trannies 'crunch' when cold, especially in the 1-2 and 2-3 shifts. But should shift perfectly when hot (and yes, mine is like that if I don't pause shifts for the first 2 miles or so). Good luck.

 

Thank you very much to everyone for taking the time to post. You have all provided me with valuable information to help me understand what is happening with my vette.

Unfortunately, I'm still waiting for the dealer to fit me in to make the corrections but hopefully once the correct fluid in in the differential all the noises will go away.

I would have never thought that a Chevy dealer would put the wrong fluids in both my transmission and differential. Go figure...

Thanks,
Paul

 

Hey Dozer,

Keep me posted on what happens at the dealership. They should be getting you in quickly to take care of this concern. If you would like me to set you up a case in my system let me know. I am here to help!

Kelly J.
Chevrolet Customer Care

 

Thank you very much Kelly! So far so good, the dealer put the correct fluid (Dexron LS) in my differential yesterday and all the noises are gone. It has only been a day but I'm very optimistic. I still have concerns about possible damage that may have been caused but right now it seems okay.

Thanks,
Paul

 

While Dexron III, Spec H, was the correct Tremec lubricant until the rights to Dexron III trademark expired back in 2007. So now the correct lubricant is manual transmission lubricant GM P/N 88861800. Dexron VI IS NOT the same as Dexron III, Specc H. While all automatics that used Dexron III can now use Dexron VI, Dexron VI IS NOT the correct lubricant for the Tremec. Use only manual transmission lubricant GM P/N 88861800.

 

Hey Paul,

I just wanted to check on ya! How are you cruising? Everything still working well for you since your visit to the dealership?

Kelly J.
Chevrolet Customer Care

 

you were concerned about the fluid that the dealer refilled your transmission with, and now you went back and they put correct/different in fluid your differential.... ok

 

Strange.

Paul, you know the transmission lubricant and the differential lubricant are not the same, correct? The Corvette does not have a trans axle. You do need the correct lubricant in the transmission too.