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j
Just had the differential rebuilt on my 1975. New half shafts and new u Joints in the driveshaft and new balanced tires. I still have a slight vibration. Anyone have ideas on how to determine what the root cause is?
The vibration seems worse after 60 MPH.
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Send PMIrving, TX - USA
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I had a vibration in my C3, but it was the steering pump.
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Send PMManteca, CA - USA
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Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
You've certainly covered most of the bases Jack. The rear wheel bearings would have to be pretty bad ( and easily checked) before causing vibration but heavily worn trailing arm bushings have been known to contribute.
Jimmy B.
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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/
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Automatic or manual trans?
Heavy vibration, or light?
Is it steady, or does it seem to come and go?
Lot of things can cause vibrations, and you've replaced a lot of stuff back there. Did you have this vibration BEFORE doing any of this, or was this the reason you did all of the work?
Does the vib. feel like it's in the rear, front, or the center of the car?
The trans or engine mounts could be sagging/soft, could be a flywheel(manual)/torque converter(automatic) out of balance, harmonic balancer on the front of the engine....so many possibilities.
Heavy vibration, or light?
Is it steady, or does it seem to come and go?
Lot of things can cause vibrations, and you've replaced a lot of stuff back there. Did you have this vibration BEFORE doing any of this, or was this the reason you did all of the work?
Does the vib. feel like it's in the rear, front, or the center of the car?
The trans or engine mounts could be sagging/soft, could be a flywheel(manual)/torque converter(automatic) out of balance, harmonic balancer on the front of the engine....so many possibilities.
Joel Adams
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j
It's a 4 speed manual. The vibration is 'slight'. I have been trying to see where it is the most noticeable. I can feel it on the shifter and also see the rear view mirror vibrate.
It seems to be dependant on RPM as it comes in and out as I accelorate through the gears.
I saw a vibration analysis check sheet from Tracey Performance, but am trying to work through all this.
The car has 116K miles on it so lots of the things you mention could be worn out. I still need to replace the shocks, but I want to drive the car in the Dream Cruise on Woodward this weekend.
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Send PMManteca, CA - USA
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Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
DUDE ! Go for it ! But try to keep it below 60,at least in the parade.
Jimmy B.
Just can't wait to get on the road again.
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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
[QUOTE=jp75vette] It seems to be dependant on RPM as it comes in and out as I accelorate through the gears.[/QUOTE]
Good info...
Now...does it seem to only vib. when accelerating, as when the drivetrain is under a load, or can you get a vib. just sitting still, with the trans in neutral, at a certain rpm?
If you are driving at a steady speed, under power, with the vib., if you put it in neutral, does it go away?
Good info...
Now...does it seem to only vib. when accelerating, as when the drivetrain is under a load, or can you get a vib. just sitting still, with the trans in neutral, at a certain rpm?
If you are driving at a steady speed, under power, with the vib., if you put it in neutral, does it go away?
Joel Adams
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j
The vibration seems to be worse while accerating and it seems to be worse at approx 1500 RPM. It also vibrates when I depress the clutch and rev the engine.
One strange thing is that the vibration really gets worse when I decelerate with the clutch in gear.
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Duncanville, TX - USA
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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
I think you may have a flywheel/clutch balance issue, OR...the pilot bushing in the crankshaft, for the trans input shaft, is worn, allowing the input shaft to run off-center, and create a vibration.
[QUOTE=jp75vette]One strange thing is that the vibration really gets worse when I decelerate with the clutch in gear.[/QUOTE]
Do you mean while you are driving at speed, and push in on the clutch, but leave the trans in gear? If so, then this would definitely point to a pilot bushing/input shaft problem...
[QUOTE=jp75vette]One strange thing is that the vibration really gets worse when I decelerate with the clutch in gear.[/QUOTE]
Do you mean while you are driving at speed, and push in on the clutch, but leave the trans in gear? If so, then this would definitely point to a pilot bushing/input shaft problem...
Joel Adams
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j
Yes that's what I did, why I'm not sure, but it really vibrated.
My plan is to pull the transmission when I put the car up on blocks for the winter. Third gear doesn't work.
I will redo the clutch at that time.
Is the pilot with a bearing worth looking at?
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