Grinding Noise when under any acceleration, help!!
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Grinding Noise when under any acceleration, help!!
Trying to diagnose the problem here before I start tearing it apart.
Here are the stymptoms:
-Terrible grinding noise when I accelerate at anything close to a reasonable rate
-The noise is worse at lower speeds. I can accelerate from 60-75 pretty hard and not really hear it, but from 0-15mph it is TERRIBLY loud pretty much no matter how slowly I accelerate
-No noise when braking hard or when "engine braking" (aka using the engine to slow the car by putting it in a low gear and letting off thc clutch)
-No noise when sitting still and letting off clutch while holding the brake (as long as the car stays still)
I'm thinking either a rear wheel bearing, something in the rear end or possibly something wrong in the torque tube.
Do you guys have any other ideas?? I'm about to pull the wheels off and see if there is anything obvious I can find now.
Here are the stymptoms:
-Terrible grinding noise when I accelerate at anything close to a reasonable rate
-The noise is worse at lower speeds. I can accelerate from 60-75 pretty hard and not really hear it, but from 0-15mph it is TERRIBLY loud pretty much no matter how slowly I accelerate
-No noise when braking hard or when "engine braking" (aka using the engine to slow the car by putting it in a low gear and letting off thc clutch)
-No noise when sitting still and letting off clutch while holding the brake (as long as the car stays still)
I'm thinking either a rear wheel bearing, something in the rear end or possibly something wrong in the torque tube.
Do you guys have any other ideas?? I'm about to pull the wheels off and see if there is anything obvious I can find now.
Instructor
Joined: Jan 2005
Posts: 213
Likes: 0
From: Port Richey Florida
Is the noise from under the motor?
Maybe a pulley tensioner, there are a couple for the ac, one on the top front passenger side , and the other one is below it next to the ac compressor.
They have bearings in them, and will make a terrible noise when they are shot.
Maybe a pulley tensioner, there are a couple for the ac, one on the top front passenger side , and the other one is below it next to the ac compressor.
They have bearings in them, and will make a terrible noise when they are shot.
Last edited by Jedster; Apr 3, 2006 at 12:49 PM.
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Any ideas?? I'm going to replace the CV joints since the seals are busted (and have been for a while) and see if that helps. I expect it won't since they somehow still have a lot of grease in them and are pretty tight. Next will be dropping the cradle and going thru the rear end/tranny/torque tube/clutch.
Any ideas?
Any ideas?
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
I would put rear of car up on jack stands and block off front wheels. Put car in gear and see if you get that same noise.
If so you'll know it's somewhere in the rear and can have somebody come over and hold gas down while you isolate the cause.
If so you'll know it's somewhere in the rear and can have somebody come over and hold gas down while you isolate the cause.
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
that doens't prove it's in the rear... could still be something in the torque tube. i did this and could get the noise but only in higher gears.. there had to have enough resistance or it wouldn't make the noise. unfortunately with my loud *** exhaust i couldn't do much to narrow down where the noise was coming from. after i get the new cv joints and axles in i'll try this again and see if i can do a better job of isolting it 
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Le Mans Master
Joined: Jun 2004
Posts: 6,752
Likes: 3
From: Bethlehem PA
sounds like a rear to me although I wouldn't rule out a torque tube issue for sure.
When my bushings went bad it was a whole different set of symptoms and made most of its noise going into gear (releasing clutch)
Grinding under load has always been a trademark of rear diff problems.
In another IRS/RWD car I had, the rear made the same noises at the same times you described and I had to replace the carriers and a few other goodies.
Keep us posted and we'll hope for the best.
Scott
When my bushings went bad it was a whole different set of symptoms and made most of its noise going into gear (releasing clutch)
Grinding under load has always been a trademark of rear diff problems.
In another IRS/RWD car I had, the rear made the same noises at the same times you described and I had to replace the carriers and a few other goodies.
Keep us posted and we'll hope for the best.
Scott
Melting Slicks
Joined: Jan 2002
Posts: 2,096
Likes: 0
From: Size Does Matter CA
Does it make noise only when you you give it gas in gear? If so rear diff is bad.
Also when you are driving at any speed take it out of gear and give it gas, any noise?? Most likely not, that means your rear diff is bad, only under stress does it make noise because the gears are working.
You will most like develop a loud whine eventually like I did. That is how I describe my noise.
Hope I helped somehow.
Also when you are driving at any speed take it out of gear and give it gas, any noise?? Most likely not, that means your rear diff is bad, only under stress does it make noise because the gears are working.
You will most like develop a loud whine eventually like I did. That is how I describe my noise.
Hope I helped somehow.
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Thanks. Those symptoms are exactly what I am experiencing. The diff. had been weird lately, chirping around sharp turns even when I wasn't giving it any gas and such.
oh well, 4:10's here I come
oh well, 4:10's here I come
Le Mans Master
Joined: Jun 2004
Posts: 6,752
Likes: 3
From: Bethlehem PA
Originally Posted by schpenxel
Thanks. Those symptoms are exactly what I am experiencing. The diff. had been weird lately, chirping around sharp turns even when I wasn't giving it any gas and such.
oh well, 4:10's here I come
oh well, 4:10's here I come
It woke the car up more than I expected it to.
I can still cruise at 90 mph in 6th gear and push ~2300 rpm
Scott
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
That's what the guy I bought the car from who had 4:10's on there before i bought it said (and everybody else 
) If that turns out not to be the problem...oh well
) If that turns out not to be the problem...oh well
Thread Starter
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Well, I replaced the rear and thought the problem was solved...a few miles into driving it started doing it again. After a few hard acceleration runs in first gear the sound has gotten MUCH worse. If rolling at say 45mph and I put the car in neutral, the noise stops. If I put the car into 1st gear while rolling you can hear the whining noise spinning up as the synchro's match the speed of the gears in the tranny. The noise is definetly coming from the torque tube/clutch area so it is most likely a bearing in the front of the torque tube IMO. It also does it in any gear under acceleration...and well, at this point pretty much anytime at all. Guess I should have spent more time making the problem/noise worse before I replaced the rear. Oh well, live and learn. Any pointers on replacing that? I know GM lists it as not servicable but I tend to believe it can be done and remember reading about some other members doing it.
Thanks for any help.
Thanks for any help.
Advanced
Joined: Apr 2006
Posts: 82
Likes: 0
From: Asheboro NC
Howdy Neighbor
While reading your thread and looking at your pictures I noticed we live in the same town. Small world huh? My 98 looks just like your car except I have chrome wagon wheels. Good luck with the fix and I'll see you around town.
Pro
Joined: Feb 2002
Posts: 606
Likes: 0
From: Virginia Beach VA
Hey Carson,
I have the OEM flex couplings and replaced the two bearings in the rear housing and the one bearing and slinger ring on the input shaft.
http://forums.corvetteforum.com/show....php?t=1367665
PM Me.
Greg K
I have the OEM flex couplings and replaced the two bearings in the rear housing and the one bearing and slinger ring on the input shaft.
http://forums.corvetteforum.com/show....php?t=1367665
PM Me.
Greg K
3rd Gear
Joined: Oct 2014
Posts: 3
Likes: 0
Grinding sound under acceleration
Trying to diagnose the problem here before I start tearing it apart.
Here are the stymptoms:
-Terrible grinding noise when I accelerate at anything close to a reasonable rate
-The noise is worse at lower speeds. I can accelerate from 60-75 pretty hard and not really hear it, but from 0-15mph it is TERRIBLY loud pretty much no matter how slowly I accelerate
-No noise when braking hard or when "engine braking" (aka using the engine to slow the car by putting it in a low gear and letting off thc clutch)
-No noise when sitting still and letting off clutch while holding the brake (as long as the car stays still)
I'm thinking either a rear wheel bearing, something in the rear end or possibly something wrong in the torque tube.
Do you guys have any other ideas?? I'm about to pull the wheels off and see if there is anything obvious I can find now.
Here are the stymptoms:
-Terrible grinding noise when I accelerate at anything close to a reasonable rate
-The noise is worse at lower speeds. I can accelerate from 60-75 pretty hard and not really hear it, but from 0-15mph it is TERRIBLY loud pretty much no matter how slowly I accelerate
-No noise when braking hard or when "engine braking" (aka using the engine to slow the car by putting it in a low gear and letting off thc clutch)
-No noise when sitting still and letting off clutch while holding the brake (as long as the car stays still)
I'm thinking either a rear wheel bearing, something in the rear end or possibly something wrong in the torque tube.
Do you guys have any other ideas?? I'm about to pull the wheels off and see if there is anything obvious I can find now.
The first thing I would check for is a broken motor mount. Sound travels funny in vettes so what's happening in the front could very well sound like the back. I would take a flashlight and check for scrapping on the fan or fan shroud, if there is you've got a bad motor mount and it will probably be on the drivers side. As the motor torques if it isn't held by the mount it will scrap against the shroud.
good luck
Safety Car
Joined: Mar 2005
Posts: 3,755
Likes: 1,214
From: Wisconsin
Ten year old thread I'll bet he's got it figured out by now. Oh and by the way, the electric fans dont move even if a motor mount was broke
Last edited by feeder82; Apr 23, 2016 at 12:34 PM.