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Topic: 1975 4 Speed Bearing noise

in Forum: C3 Driveline Components


1975 4 Speed Bearing noise

Posted: 2/23/15 9:48am Message 1 of 6
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Bethlehem, PA - USA
Joined: 2/13/2014
Posts: 9
Vette(s): 1975 Stingray currently, 1971, 1989,1992, 1995, 2001

Howdy Gents,


I have a 1975 Stingray with the standard 4 speed and she's making a bearing noise. I thought it might be a throw out bearing, but it happens when the transmission is turning. The clutch can be either depressed or not. Haven't heard of this before. The previous owner said he went to a Chevy dealer and they said "Not a big deal". It is annoying and kind of loud. You can hear it on the side of the street as I go by. I haven't taken it to a Trans place yet. Just wanted some opinions before I take it in and get lied to. Maybe low fluid ??.  Thanks for your help !!


Bruce 




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Re: 1975 4 Speed Bearing noise

Posted: 2/23/15 10:28am Message 2 of 6
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20218
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
Start the engine, foot on the brake, mash the clutch IN, and put the trans in gear(any gear). At that point, there is NOTHING in the trans turning. If the noise is still there, then it is either the throw-out bearing, or the pilot bushing.
If the noise stops with it in gear, clutch down, then you definitely have a trans noise. How bad it is would determine if it needs to be repaired soon.


Joel Adams
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Re: 1975 4 Speed Bearing noise

Posted: 2/23/15 11:28am Message 3 of 6
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Bethlehem, PA - USA
Joined: 2/13/2014
Posts: 9
Vette(s): 1975 Stingray currently, 1971, 1989,1992, 1995, 2001

Thanks Joel,


I am 99% sure it is a trans noise. I am not familiar with issues with these 4 speed transmissions. Is it common for a 40 year old, 75K mile trans to make noise?? Is it a "Main" bearing, or some other bearing that goes in these transmissions?? I thought someone out there had the same issue with these transmissions. I have had manual transmissions before and they were pretty much trouble free.  I don't believe it was raced or abused. Thanks again


Bruce




Re: 1975 4 Speed Bearing noise

Posted: 2/23/15 4:05pm Message 4 of 6
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Grapevine, TX - USA
Joined: 8/26/2006
Posts: 1529
Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport M7 convertible.
My 4 speed bearings were shot and very noisy when I had mine overhauled.  You could spin them on your fingers and hear the bearings hiss loudly.


   

Re: 1975 4 Speed Bearing noise

Posted: 2/23/15 8:44pm Message 5 of 6
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20218
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
KSNBRUCIE said:The clutch can be either depressed or not.

This is why I suggested putting it in gear with the clutch depressed.
The four speeds can make what some would consider "normal" noises, but...if you can hear it whining/growling as you drive past a building, then it's prolly too loud, and should be looked into.
Bearing kits are fairly reasonable, price-wise, as long as you get a real, name brand kit. Cheaper kits will have cheaper, off-shore bearings that may make more noise than what you have now.



Joel Adams
C3VR Lifetime Member #56    

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(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: 1975 4 Speed Bearing noise

Posted: 2/24/15 1:18pm Message 6 of 6
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Germansville, PA - USA
Joined: 1/28/2010
Posts: 862
Vette(s): 1974 Coupe 358ci 4 speed Black w/Medium Saddle interior w/79 custom leather seats. . 1999 C5 Convertible, 6 speed, Atomic orange, Oak interior.
Had a noise with my 4 speed and pulled it out and took to tranny shop. When guy there picked up the tranny out of my pick up truck he said something didn't "feel" right. He pulled off front nose cover and the front input shaft bearing came out in pieces. Ouch


   

DanT

in Forum: C3 Driveline Components


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