MN6 T6060 problem? Synchros?
Thread Starter
Team Owner
Joined: Aug 2000
Posts: 28,015
Likes: 32
MN6 T6060 problem? Synchros?
I thought my 2008 MN6 was "clunky" to say the least. But tonight I drove it down to the store. Temps were at normal operating range.
But anywhere above 15mph I can't put it into first gear. It's like it's locked out. One time it managed to go in it kinda grinded.
Then upshifts from 1->2, 2->3, 3->4 take an extra second or two from pushing into the clutch, before it will go into the gear. Once it gets in the gear like a half second later it "clunks" and I can feel the vibration in the shifter.
Is this a synchro problem?
But anywhere above 15mph I can't put it into first gear. It's like it's locked out. One time it managed to go in it kinda grinded.
Then upshifts from 1->2, 2->3, 3->4 take an extra second or two from pushing into the clutch, before it will go into the gear. Once it gets in the gear like a half second later it "clunks" and I can feel the vibration in the shifter.
Is this a synchro problem?
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
I think it could be one of several things incl. synchros. Have you looked at your fluid recently? It could be clutch master, slave cylinder, actual gears, internal gear alignment, etc. It may be time to see a dealer service dept.
Racer
Joined: Apr 2007
Posts: 255
Likes: 0
From: Shrewsbury MA
Interesting that you mention the clunk. My 2008 (which is rough/notchy on the 1-2 and 2-3 upshifts when cold) clunks on the 1-2 upshift when warm just as the shifter is pulled through neutral (as 1st disengages). This happens on easy shifting, clutch fully in, at low to moderate RPM. This clunk does not happen on any other gear change, just the 1-2 upshift.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
Sad, yes, but things can go wrong or break with less miles than that. I'd eliminate nothing from potential issues. We've read here of one person who jammed a couple of misses into 5th upshifts and ruined his trans.
Melting Slicks
Joined: May 2004
Posts: 3,017
Likes: 2
I have a 2008 and when new (<3000 miles) the trans had a notchy 1-2 shift when temps were less than 40 degrees. I changed the fluid to Redline D4 ATF, and it helped the cold shifts, but not a lot. I now have 10K miles on the trans and it shifts like butter. What you are describing is not normal, I would get it looked at. There was a least one buy back on a Z because of the 6060 trans, and several transmissions were replaced due to some clearance issues with gears/syncros..
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
Melting Slicks
Joined: Feb 2004
Posts: 3,307
Likes: 110
From: Tucson AZ
I ran across two 2008 Z06 cars that were manufacturer buybacks because of transmission shift problems.
I would check your clutch fluid first, then if that does not fix it go straight to the dealer. Make sure you document everything.
I would check your clutch fluid first, then if that does not fix it go straight to the dealer. Make sure you document everything.
Pro
Joined: Mar 2008
Posts: 620
Likes: 3
From: Harwood Heights IL
I have a 2008 and when new (<3000 miles) the trans had a notchy 1-2 shift when temps were less than 40 degrees. I changed the fluid to Redline D4 ATF, and it helped the cold shifts, but not a lot. I now have 10K miles on the trans and it shifts like butter. What you are describing is not normal, I would get it looked at. There was a least one buy back on a Z because of the 6060 trans, and several transmissions were replaced due to some clearance issues with gears/syncros..
Safety Car
Joined: Oct 2008
Posts: 4,908
Likes: 265
From: Charleston SC
I'd change the oil...matter fact, I'm getting ready to do that on mine.
OP, Every single car I have had with a manual, regardless of bran, always were touchy going back into first gear at anything less than 10mph. I would not concider that a problem. You don't want to force anything either, which is when people break stuff inadvertently.
OP, Every single car I have had with a manual, regardless of bran, always were touchy going back into first gear at anything less than 10mph. I would not concider that a problem. You don't want to force anything either, which is when people break stuff inadvertently.
Race Director
Joined: Jun 2005
Posts: 10,904
Likes: 2,694
From: Phila Suburbs 2023 C8 & 2013 650ix
I've got to disagree. The T-6060 should go into first gear at a stop every single time unlike the original transmission in the 05 to 07's. There is a problem if it doesn't.
Melting Slicks
Joined: Sep 2008
Posts: 2,360
Likes: 59
From: San Jose California
The OP did say under 15 mph, so that is rolling. I did have mine not go into gear from a stop once. It hasn't done it since then, I had to put it in second before it would finally go into first.
Here's the issue with that, it has to do it more than 5% of the time before GM will consider it above normal. 5% might not sound like alot, but if you think of how mant times you come to a complete stop, it is.
I would bring it to the dealer before changing the fluid.
Here's the issue with that, it has to do it more than 5% of the time before GM will consider it above normal. 5% might not sound like alot, but if you think of how mant times you come to a complete stop, it is.
I would bring it to the dealer before changing the fluid.
