Manual trans fluid recommendation
Safety Car
Joined: Sep 2007
Posts: 3,502
Likes: 82
I can recommend NOT installing Mobil 1 Synthetic in the transmission if you are looking for improved shifts. It made virtually no change in driveability and thinned my wallet by about $30.00 in my 2009 C6. It was a waste of time and energy.
Safety Car
Joined: Feb 2008
Posts: 3,712
Likes: 3
From: TEXOMA
St. Jude Donor '08-'09
I put some AMSOIL Univeral ATF and am NOT impressed. apparently there is a New formula out there thats supposed to be better and sold under the same name. i guess i got shipped the old shyt! GRRRR.. going back to the GM stuff soon.
-carl
-carl
Melting Slicks
Joined: Jul 2007
Posts: 2,052
Likes: 14
Royal Purple in my KB Cobra since the trans was terrible... after about 2-3K miles, it was amazing (no difference just after swap). You would never know there was a problem on 2nd and 3rd. The 1st thing I will do with my next M6 C6 will be RP fluid. 
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Thread Starter
Pro
Joined: Mar 2008
Posts: 620
Likes: 3
From: Harwood Heights IL
Drifting
Joined: Apr 2006
Posts: 1,276
Likes: 5
From: Ambler Pa.
I'm using Royal Purple Syncromax. Significant overall improvement. Gets better after some miles , as with any fluid in these transmissions, shifting is better after warm up.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
I tried the RP and it made the condition worse. I drained it and put in Mobil syn ATF. After the change to the Mobil, I couldn't really tell the difference between it and the factory fill, maybe a little better when the transmission was cold.
Some have reported that Redline ATF helped, but I haven't tried it. Will most likely try the Redline later on. I now have about 5,000 miles on my 09 Z06, and the shifting has improved a little, but still not like it should be. Sunday I had my 56 out that I have a '70 Muncie WR 4-speed(with a Hurst shifter, and a repro handle) in it. The Muncie is louder then the Z06 but it shifts about the same but smoother then the Z06. The Muncie dosen't nibble or grind when shifting.
Some have reported that Redline ATF helped, but I haven't tried it. Will most likely try the Redline later on. I now have about 5,000 miles on my 09 Z06, and the shifting has improved a little, but still not like it should be. Sunday I had my 56 out that I have a '70 Muncie WR 4-speed(with a Hurst shifter, and a repro handle) in it. The Muncie is louder then the Z06 but it shifts about the same but smoother then the Z06. The Muncie dosen't nibble or grind when shifting.
Last edited by JoesC5; Jul 23, 2009 at 02:23 PM.
Pro
Joined: Mar 2004
Posts: 653
Likes: 0
For a street car, Castrol cheap stuff at $12/gallon is my favorite. Very smooth shifting at operating temps, slightly notchy shifting below 40degF but I haven't found a fluid that isn't.
For a street and track car, Amsoil TorqueDrive is my new favorite. It wouldn't hurt anything but your wallet to use this fluid on the street, too.
For a street and track car, Amsoil TorqueDrive is my new favorite. It wouldn't hurt anything but your wallet to use this fluid on the street, too.
Melting Slicks
Joined: Jul 2007
Posts: 2,052
Likes: 14
Nope, it was the Synchromax, not ATF. I should have been more specific. It worked with in a few months and again, it will be the first thing I add to my next C6/C6Z. My Cobra took just over 2 bottles if I remember correctly.
http://www.royalpurple.com/manual-tr...ion-fluid.html
http://www.royalpurple.com/manual-tr...ion-fluid.html
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 32
From: Central Florida
I run the manufacturer's specified GM-brand fluid in my transmissions.
I tried some aftermarket fluids three Corvettes ago and found the shifter feel changed in ways I didn't like.
So stock fluid is what I recommend. I do change mine at 8k-10K intervals because I track the car.
Equally important to tranny performance is keeping the clutch fluid clean so that the clutch hydraulics behave normally.
Most tranny issues flow from
(1) mis-behaving clutch
(2) driver error during shifts, including power-shifting synchronization issues
(3) wasted tranny fluid
I've had zero tranny issues racing three Z06s.
Ranger
I tried some aftermarket fluids three Corvettes ago and found the shifter feel changed in ways I didn't like.
So stock fluid is what I recommend. I do change mine at 8k-10K intervals because I track the car.
Equally important to tranny performance is keeping the clutch fluid clean so that the clutch hydraulics behave normally.
Most tranny issues flow from
(1) mis-behaving clutch
(2) driver error during shifts, including power-shifting synchronization issues
(3) wasted tranny fluid
I've had zero tranny issues racing three Z06s.
Ranger
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,404
From: Bethesda MD
Have you driven the 6060 transmission in cold weather? There is an issue on the 1-2 (and sometimes the 2-3) for a lot of 2008 and 2009 owners. After 5 - 10 miles of warm-up the notchiness goes away. Some of us are looking at a fluid change to see if better cold start-up propoerties can be found.
Race Director
Joined: Aug 2000
Posts: 10,649
Likes: 32
From: Central Florida
Have you driven the 6060 transmission in cold weather? There is an issue on the 1-2 (and sometimes the 2-3) for a lot of 2008 and 2009 owners. After 5 - 10 miles of warm-up the notchiness goes away. Some of us are looking at a fluid change to see if better cold start-up propoerties can be found.
I've driven five different Corvettes with the 6060. Sweetest tranny ever in a Covette. But like all Corvette trannies, it requires that the driver be patient until the driveline is warmed by driving the car.
Just a thought.
Ranger
Melting Slicks
Joined: Apr 2007
Posts: 3,290
Likes: 0
From: Willow Springs IL
I just had a new RPM stage 5 trans built and installed by RPM in my A&A supercharged 07. They filled the trans with O'Reilley parts store Dextron and said that's what they use. It's all the same.
Melting Slicks
Joined: Jul 2007
Posts: 2,052
Likes: 14
Do what you want.
Tremec T56 in my Cobra with 20K mile stock fluid = suck at grinding and hanging up in neutral and speedshifting.
Tremec T56 in my Cobra with Syncromax fluid = speedshifting with no worries about 2nd or 3rd and zero hanging in neutral.
Do what you want but I am sure everything, including GM fluid, can be improved upon. Not to mention that we all know 3-5 rwhp can be found by going to a higher quality sysnthetic lube......I hope we know that anyway.
Tremec T56 in my Cobra with 20K mile stock fluid = suck at grinding and hanging up in neutral and speedshifting.
Tremec T56 in my Cobra with Syncromax fluid = speedshifting with no worries about 2nd or 3rd and zero hanging in neutral.
Do what you want but I am sure everything, including GM fluid, can be improved upon. Not to mention that we all know 3-5 rwhp can be found by going to a higher quality sysnthetic lube......I hope we know that anyway.
Drifting
Joined: Mar 2005
Posts: 1,424
Likes: 21
From: Placitas New Mexico
I've driven a 2009 Z06 in late November. It's cold-weather start-up tranny behavior was very similar to what I've experienced in all the C5s and C6s I've driven. Once the driveline is warmed up (surrogate=oil temp above 100*F), shifter action smoothes out.
I've driven five different Corvettes with the 6060. Sweetest tranny ever in a Covette. But like all Corvette trannies, it requires that the driver be patient until the driveline is warmed by driving the car.
Just a thought.
Ranger
I've driven five different Corvettes with the 6060. Sweetest tranny ever in a Covette. But like all Corvette trannies, it requires that the driver be patient until the driveline is warmed by driving the car.
Just a thought.
Ranger
I just skip 2nd gear for the 1st 10-15 minutes