Vibration in drivetrain
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From: Pensacola Florida
Vibration in drivetrain
I accelerated through second hard, I pushed the clutch in and the stick shift would not come out of second. I have a 402 with 490 rwhp through a textralia clutch, t56, and stock 3.42 rear. I just installed 335 Michelin PS2s on the rear and the traction is better, however now, obviously, the driveline is suffering. I was able to move the gear shift out of second once the RPMs hit 5000. I put it into fourth and continued down the road. However, now when the clutch is engaged the driveline has a horrible vibration, almost unbearable around 3k RPMs and higher. The trans is difficult to shift into first, second and third. If I move through the gears quickly, just moving the shifter in and out of gears, I can cause a quick grind, even with the clutch fully disengaged. When in gear, at RPMs above 4500, the gear shift is stuck. What could be the issue? It feels like something is bent. Thanks for the help.
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From: Pensacola Florida
Yeah- I think it is too. However, the vibration is strong and I had no idea there were parts in the trans that could bend or come out of line like that. I thought the trans would just break instead of continue to shift and drive. It makes me wonder if I could have more than one problem. Possibly both a trans issue and a torque tube problem. The vibration is strong and makes me feel like it is a large piece that is out of line. I don't know. It shifts fine through all the gears driving at normal speeds. Above 5000 is when the gear shift won't disengage from the gear. The vibration is RPM dependent (increases as the RPM increases, only while the clutch is engaged). Thanks for the input. All is appreciated. -Rusty
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Rusty,
Where are you located? You might want to fill out your sig. Might have someone near to compare your vette too.
With the clutch pedal out the propshaft is rotating while in neutral. Try reving the car up in neutral and see if you get the same vibration. This will tell you if it is or is not something to do with the propshaft.
Where are you located? You might want to fill out your sig. Might have someone near to compare your vette too.
With the clutch pedal out the propshaft is rotating while in neutral. Try reving the car up in neutral and see if you get the same vibration. This will tell you if it is or is not something to do with the propshaft.
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From: Pensacola Florida
The engine revs as normal without vibration while the clutch is depressed. Also, when driving, the vibration goes away when I depress the clutch. So the vibration is surely in the driveline. Thanks Eric for your input. I am in Southern Pines, NC. Hoping for more help.
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From: Howell Michigan
St. Jude Donor '09-'10-'11
I guess I didn’t explain myself very well in the last message. 
You need to run the engine with the car stationary with it in neutral to see if it is propshaft or final drive related. If it vibrates while stationary with the clutch pedal out and the trans in neutral then you most likely have a propshaft, trans input shaft issue. If it doesn’t vibrate it could be anything from the trans to the rear tires. If it does vibrate while in neutral and with the car stationary also note what engine rpm seems to be the worse. 
You need to run the engine with the car stationary with it in neutral to see if it is propshaft or final drive related. If it vibrates while stationary with the clutch pedal out and the trans in neutral then you most likely have a propshaft, trans input shaft issue. If it doesn’t vibrate it could be anything from the trans to the rear tires. If it does vibrate while in neutral and with the car stationary also note what engine rpm seems to be the worse.
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From: Pensacola Florida
When stationary and in neutral there is no abnormal vibration through all RPMs. The only vibration is during movement with the driveline engaged (clutch engaged, pedal out) so it is related to anything behind the propshaft. I know it is not the tires, wheels, or halfshafts because there is no vibration with the clutch disengaged and with the vehicle rolling. I feel it is the driveshaft or transmission. The vibration is violent (shakes the entire car) from 3000rpm and up. Still not sure what to target when I finally have time to get it apart. Any help would be appreciated (ie if anyone has had the same experience). I also appreciate your help Eric. -Rusty
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From: Howell Michigan
St. Jude Donor '09-'10-'11
When stationary and in neutral there is no abnormal vibration through all RPMs. The only vibration is during movement with the driveline engaged (clutch engaged, pedal out) so it is related to anything behind the propshaft. I know it is not the tires, wheels, or halfshafts because there is no vibration with the clutch disengaged and with the vehicle rolling. I feel it is the driveshaft or transmission. The vibration is violent (shakes the entire car) from 3000rpm and up. Still not sure what to target when I finally have time to get it apart. Any help would be appreciated (ie if anyone has had the same experience). I also appreciate your help Eric. -Rusty
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From: Pensacola Florida
That's right, when stationary with the clutch disengaged (pedal to the floor) there is no abnormal vibration. Vibration is only caused when moving with the clutch engaged (pedal all the way out) and in all gears above 2500rpm. Hope that helps clarify a bit. Thanks
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From: Howell Michigan
St. Jude Donor '09-'10-'11
If you wish to narrow down what the issue is you need to test the car while stationary, trans in neutral and the clutch engaged, pedal full up, and sweep through the rpm range to see if you get the vibration. If you do, report back what rpm it seems to be the worse.
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From: Pensacola Florida
I went ahead and got in the vette today. I did what you said and had it stationary, in neutral, and with the clutch engaged. I noticed this time the vibration is present both when the clutch is engaged and disengaged. The vibration is noticeable throughout the rpm range. When sweeping from idle to 5000, with the trans in neutral and the clutch engaged (pedal fully up) the vibration is hardly noticeable at idle, increased at 2000, is very strong at 3500, decreases slightly from 4000-5000. So the worst is at 3500. At 3500 I depressed the clutch pedal and there was no difference in the vibration. Hope this test sheds some light. Thanks for the help again. -Rusty
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Rusty,
It's classic engine imbalance. Stock flywheels have holes just inside from the starter ring gear. Weights can be added to correct the imbalance With the right equipment it can be done in vehicle.
It's classic engine imbalance. Stock flywheels have holes just inside from the starter ring gear. Weights can be added to correct the imbalance With the right equipment it can be done in vehicle.
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From: Pensacola Florida
Why do you think it started so abruptly (during hard acceleration). Could one of these weights have been thrown out? I never noticed imbalance prior to the incident. Thanks. It feels good to narrow this down and I truly appreciate the help from an experienced individual.
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St. Jude Donor '09-'10-'11
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I accelerated through second hard, I pushed the clutch in and the stick shift would not come out of second. I have a 402 with 490 rwhp through a textralia clutch, t56, and stock 3.42 rear. I just installed 335 Michelin PS2s on the rear and the traction is better, however now, obviously, the driveline is suffering. I was able to move the gear shift out of second once the RPMs hit 5000. I put it into fourth and continued down the road. However, now when the clutch is engaged the driveline has a horrible vibration, almost unbearable around 3k RPMs and higher. The trans is difficult to shift into first, second and third. If I move through the gears quickly, just moving the shifter in and out of gears, I can cause a quick grind, even with the clutch fully disengaged. When in gear, at RPMs above 4500, the gear shift is stuck. What could be the issue? It feels like something is bent. Thanks for the help.
I understand the weights coming off flywheel will cause a vibartion, but I was reading that he is having trouble with the transmisssion, getting it in and out of gears, and that could be some internal problems, along with the balance issue..
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From: Pensacola Florida
Yeah- I have spoke with several reputable mechanics and they wonder if it could be something more than just a weight. There is no way the vibration was present before the incident so in no way am I going to just add weights to the flywheel. I need to ID the problem. One mechanic sugggested that a clutch plate may have broken and this is the cause of the difficult shifting and vibration all in one. I wish to have more opinions on this subject before I tear into the car. Thanks for the suggestions and open to thoughts.
