3rd Gear Synchro
Thread Starter
Drifting
Joined: Oct 2004
Posts: 1,756
Likes: 267
3rd Gear Synchro
My 2011 GS MN has a less than perfect 3rd gear synchronizer. There's a small 'catch' or grind if I try to shift into 3rd too quickly. If I pause for a fraction of a second to let the synchro do its thing, the shift is smooth. Has anyone else experinced this problem? Is there a fix in the way of chemistry (additive or different tranny fluid)? Car has 1400 miles on it.
Burning Brakes
Joined: Sep 2009
Posts: 959
Likes: 3
From: Hartford CT
On my T56, 3rd seems a little notchy when shifted fast, but never grinds. I have found this to be the case on all C6s I have driven. My guess is that your trans is normal. See if you can find another 08+ C6 you can drive.
Supporting Vendor
Joined: Apr 2011
Posts: 3,332
Likes: 195
From: Frederick Maryland
St. Jude Donor '08-'09-'10-'11-'12, '14-'15-'16-'17-'18
My 2011 GS MN has a less than perfect 3rd gear synchronizer. There's a small 'catch' or grind if I try to shift into 3rd too quickly. If I pause for a fraction of a second to let the synchro do its thing, the shift is smooth. Has anyone else experinced this problem? Is there a fix in the way of chemistry (additive or different tranny fluid)? Car has 1400 miles on it.
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Intermediate
Joined: May 2011
Posts: 33
Likes: 0
From: Naperville Illinois
Ditto. New coupe, under 1000 miles. When cold it feels a bit notchy in shifting from 2nd to 3rd. At first I thought I wasn't depressing the clutch far enough but observation proved that thesis invalid. Guess we just live with it.
Pro
Joined: Jun 2005
Posts: 693
Likes: 2
From: Los Angeles CA
'05 Z51. i also have the same small catch/grind sometimes when shifting fast into 3rd.
i've had my trans rebuilt due to some broken ring that was causing big grinds, but it still has the small catch/grind when trying to shift fast (not necessarily high rpm it seems, just when rushed).
i figure it's my shifting technique (pushing of clutch maybe too early vs. pushing into 3rd?), since i see plenty of videos such as ranger drag strip runs where 3rd shift happen much much faster.
like you, as long as i give it that fraction of a sec more when shifting into 3rd, the synchros seem to be able to make up for my imperfect timing.
i've had GM fluid, Royal Purple Synchromax, then back to GM fluid after trans rebuild, but nothing can make up for my lazy/fast shifts.
i've had my trans rebuilt due to some broken ring that was causing big grinds, but it still has the small catch/grind when trying to shift fast (not necessarily high rpm it seems, just when rushed).
i figure it's my shifting technique (pushing of clutch maybe too early vs. pushing into 3rd?), since i see plenty of videos such as ranger drag strip runs where 3rd shift happen much much faster.
like you, as long as i give it that fraction of a sec more when shifting into 3rd, the synchros seem to be able to make up for my imperfect timing.
i've had GM fluid, Royal Purple Synchromax, then back to GM fluid after trans rebuild, but nothing can make up for my lazy/fast shifts.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
'05 Z51. i also have the same small catch/grind sometimes when shifting fast into 3rd.
i've had my trans rebuilt due to some broken ring that was causing big grinds, but it still has the small catch/grind when trying to shift fast (not necessarily high rpm it seems, just when rushed).
i figure it's my shifting technique (pushing of clutch maybe too early vs. pushing into 3rd?), since i see plenty of videos such as ranger drag strip runs where 3rd shift happen much much faster.
like you, as long as i give it that fraction of a sec more when shifting into 3rd, the synchros seem to be able to make up for my imperfect timing.
i've had GM fluid, Royal Purple Synchromax, then back to GM fluid after trans rebuild, but nothing can make up for my lazy/fast shifts.
i've had my trans rebuilt due to some broken ring that was causing big grinds, but it still has the small catch/grind when trying to shift fast (not necessarily high rpm it seems, just when rushed).
i figure it's my shifting technique (pushing of clutch maybe too early vs. pushing into 3rd?), since i see plenty of videos such as ranger drag strip runs where 3rd shift happen much much faster.
like you, as long as i give it that fraction of a sec more when shifting into 3rd, the synchros seem to be able to make up for my imperfect timing.
i've had GM fluid, Royal Purple Synchromax, then back to GM fluid after trans rebuild, but nothing can make up for my lazy/fast shifts.
Your symptoms are not normal. A good rebuild doesn't grind. I had two bad ones and now have a good one. Might want to get it redone if still in warranty.
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Advanced
Joined: Feb 2011
Posts: 59
Likes: 0
From: Nacogdoches, TX
I am having the same problem with my stage 3 t56 rebuild. The guy who rebuilt the trans said to bleed the clutch? All the fluids have been changed out and my 3rd gear grinds at high RPM shifts only unless I pause for a split second. I am still under warranty and can now suggest that it could be the 3rd gear blocker ring.
