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#1 |
![]() Join Date: Jul 2013
Location: Atlanta
Posts: 451
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My transmission has always had the "rocks in a can" noise with the clutch engaged - disengage it and it gets quiet. But this is a new noise, I heard before on a couple rare occasions but just today got really frequent, like almost every trip through the gears. It's a loud whine/growl (fairly low-pitched) that is momentary, when I disengage the clutch and shift. It seems to happen as I'm either leaving one gear, or going into the next gear. Once in gear, or in neutral, and it's gone. It doesn't happen on every shift, but happened on a bunch right at the end of a 250 mile journey this afternoon. Does this sound like a throwout bearing going bad?
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Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG] |
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#2 |
![]() Join Date: Jul 2013
Location: Atlanta
Posts: 451
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I should mention the transmission shifts smooth, solid and tight, no issues. And the car accelerates just as strong as ever, so there's no clutch slip going on either.
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Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG] |
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#3 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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Is there a change where the clutch is releasing?
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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#4 |
![]() Join Date: Apr 2004
Location: ATL. GA.
Posts: 2,170
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Have you changed the fluid?
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Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold |
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#5 |
![]() Join Date: Jul 2013
Location: Atlanta
Posts: 451
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No and no.
![]() I have another 250 mile drive tomorrow morning to get home, and since I'll be spending most of the time in 6th (and minimize shifting) I don't think it will be a problem. Not a job I look forward to doing on the garage floor. I may just take it to a local transmission shop I know does good work.
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Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG] |
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#6 |
![]() Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,384
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May be the pilot bearing/bushing.
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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#7 |
![]() ![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
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X2 I wuz going to say the same thing; pilot bushing/bearing or throwout...would be my guess, based on the description.
The only thing about removing the drive line on the C4s is the C-beam. One: It should be properly centered to reduce wear and noise on the U joints. Bill Boudreau )at (602) 319-6575) can provide some 48mm and the 28mm gauges for that purpose, OR you can make some yourself, easily enough. ![]() Bill also provides C-beam plates which IMO are worth every penny, especially if you have big hands.
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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#8 | |
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Location: South Dakota/California
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Yep............got to ALWAYS pay attention to Ole Jerry and Ole Paul ![]() Them guys know stuff ![]() TRANSMISSION Pilot Bearing ZR-1 Transmission Install and Lift Tricks Vibration Issues Diagnosis Throwout Bearings and Clutch Forks C4 Beam Plates and Installation Bill's C-Beam Plates
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 01-03-2015 at 08:58 AM. |
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#9 |
![]() Join Date: Jul 2013
Location: Atlanta
Posts: 451
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Absolutely, thank you for the help guys. I drove the car back home yesterday, another 250 miles and everything was just fine. It still made that whirring noise occasionally, but not as frequent. I tried to use the clutch quickly and sparingly, limiting the engagement of the throwout bearing. It was also raining the whole trip back, so I'm wondering if that kept things a little cooler, since it wasn't as frequent. It used to be clattery with the clutch out, quiet with the clutch in. Now it's still clattery with the clutch out, but different-noisy with it in and I get that whirr on occasion.
One thing is for sure, when I get in there I'll be replacing all the wear items - pilot, throwout and clutch disc, and I'll assess the flywheel then. Not really interested in a lightweight like a Fidanza, but something a bit lighter than stock might find its way in there, depending on budget and wifely tolerance.
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Mark '90 ZR-1 #1322 Daily Driver, 64k and counting Black/Gray [IMG]http://i208.photobucket.com/albums/bb49/mlitherland/IMG_0326_zps3d50d8cb.jpg[/IMG] |
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#10 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
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When my Throwout went South it made a similar noise, but the release moved up as the bearing began to come apart. Sounds like the pilot bearing
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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