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Topic: C3 rear end grinding noise under torque..

in Forum: C3 Driveline Components

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C3 rear end grinding noise under torque.. (1/4)
 3/28/19 7:40pm
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Keiier, TX - USA

1969 C3, 350, Cortez Silver, Gunmetal interior, 68K miles

Joined: 3/26/2019
Posts: 1

Just started  getting a grinding noise on the rear end of my C3 when accelerating or under torque. When foot is off the accelerator the grinding noise goes away.  Any ideas out there what it may be?

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Re: C3 rear end grinding noise under torque.. (2/4)
 3/28/19 9:19pm
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Overland Park, KS - USA

1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 692

Welcome to the forum. Most likely suspects would be rear wheel bearings or rear end differential gears.


1973 L-82 4 spd

Re: C3 rear end grinding noise under torque.. (3/4)
 3/28/19 10:02pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

#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

Joined: 11/8/2003
Posts: 19854

...or possibly the front diff mount. If it is bad, it can allow the diff to move upward under acceleration. 
Is the noise a growl/vibration, or a whine?

Joel Adams
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Re: C3 rear end grinding noise under torque.. (4/4)
 4/3/19 5:29am
lukesvetteLifetime Member
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1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.

Joined: 5/18/2004
Posts: 6810

If you hear a distinct clunk when you accelerate from a stop, the differential bushing coul be your culprit and if youíve never changed it, itís cheap insurance to try that first. Are they the original wheel bearings? Thatís a likely suspect also. Have you changed the differential fluid? If so and you are proper additive for the posi, that would be my third place guess. Good luck!!👍

|UPDATED|4/3/2019 2:29:59 AM (AZT)|/UPDATED|
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