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chattering gears

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chattering gears

Posted: 11/19/12 6:48pmMessage 1 of 6
r
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Suffolk, VA - USA
Joined: 7/24/2012
Posts: 140
Vette(s): 2009 Convertible 3LT

My 69 427 with 4 speed manual will make a chattering sound when I start off from first gear. When I bought the car the owner said that the rear gears were changed to 4.11. He gave me the old gears. I am not sure which ratio they are. I am not really sure if his information about the current gears are correct.  Could there be something not in sync? clutch issues? It shifts smooth through all gears. maybe the fluid needs to be changed? maybe the limited slip additive was not added ?  Is changing the rear fluid a hard job? Any suggestions are welcome. Bob

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Re: chattering gears

Posted: 11/19/12 8:22pmMessage 2 of 6
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Red Lion, PA - USA
Joined: 10/27/2006
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Vette(s): 1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic
Does it only do this when letting out the clutch in first gear or does it do it other times? does it make noise or just feel it chatter the whole car? It could be many things, probably going to need more information. It could be a clutch/flywheel chatter, it could come from the rear, it could even come from a rear wheel bearing maybe even a tight brake. Someone else will chime in and offer other more information. Best of luck in finding it.
Rodney

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Re: chattering gears

Posted: 11/20/12 10:59amMessage 3 of 6
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 22715
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
1st suspect would be clutch itself, including the disc, pressure plate, and/or flywheel. Could also be a worn/missing pilot bushing. Oil on the clutch disc from either the engine, or the trans, will create a chatter. A worn disc, glazed flywheel/pressure plate would too.
Does the chatter feel like it is from the rear area of the car, or more toward the front? Posi clutch chatter usually only happens when turning, but if the posi clutches are really worn, they could possibly chatter in a straight line.

If you have the old gear set out loose, look around the outer edge of the ring gear. You should see some numbers engraved on it. That will give the the ratio of that gear set. You'll see two numbers separated by a slash....for a 4.10, for instance, you might see a 10/41, the 10 being the pinion tooth count, and the 41 being the ring gear tooth count. Or....you could just count the teeth, then divide the ring gear by the pinion gear, and that is the ratio. Remember to round up...Thumbs Up





|UPDATED|11/20/2012 10:59:31 AM (AZT)|/UPDATED|

Joel Adams
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Re: chattering gears

Posted: 11/19/12 8:43pmMessage 4 of 6
r
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Suffolk, VA - USA
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Vette(s): 2009 Convertible 3LT
It only appears when you first start off from a stop. The other gears are fine and it shifts smooth.
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Re: chattering gears

Posted: 11/19/12 8:51pmMessage 5 of 6
r
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Suffolk, VA - USA
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Vette(s): 2009 Convertible 3LT

to add to my last post. The sounds come from the rear and are when you are letting out the clutch in first gear.  The car vibrates and shutters slightly until you fully release the clutch.   Thanks for the information

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Re: chattering gears

Posted: 11/20/12 11:01amMessage 6 of 6
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
You could add a bottle or two of positrack additive to the differential, drive in figure 8s a few times, and see if that makes ANY difference at all in the chattering. If it does not, then I would say you're looking at a clutch issue.

Joel Adams
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