[TheMirror]

Cheers all -



Curious what the possible causes could be for a brief high frequency driveline shudder on a 6 speed coupe. It occurs after tipoff from a rest, with the clutch fully engaged. It is not clutch shudder. Once the engine is past 1300 rpm or so, its gone. It idles fine, no roughness, no shake.

Thoughts?



-Mirror

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[flash]

quite possibly a soggy motor mount - might not be toast yet, but collapsing under load - once the intial torque load of startoff is relieved, then it lifts up enough to clear



could also be a torque tube bearing - same kind of thing - side load at startoff



when you say engaged, do you mean pedal depressed?



sitting still, does it do it out of gear clutch released?



sitting still, does it do it in gear clutch released?



rolling down the road, letting the rpms drop to idle, does it do it when you re-engage?



does it do it when launching in reverse?

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[TheMirror]

Thanks, flash. Answers in the quote below. This was a test drive, so my data is limited. I do not believe the motor mounts have been replaced in this car, and its now 11 years old....



[quote name='flash' date='Mar 16 2006, 09:42 AM']quite possibly a soggy motor mount - might not be toast yet, but collapsing under load - once the intial torque load of startoff is relieved, then it lifts up enough to clear



could also be a torque tube bearing - same kind of thing - side load at startoff



when you say engaged, do you mean pedal depressed? No, pedal out, car in gear and rolling.



sitting still, does it do it out of gear clutch released? No.



sitting still, does it do it in gear clutch released? Not idling, only under throttle application



rolling down the road, letting the rpms drop to idle, does it do it when you re-engage? Not that I remember, I don't believe I performed that test.



does it do it when launching in reverse? Yes.

[right][post="17419"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[flash]

ok - do a couple of start-offs in 2nd gear (3rd too if you can) - if it does it in all gears, then you are likely at motor mounts or torque tube bearings



the next thing to do is get it on a lift, have someone in the car do the startoff thing while in the air, and listen for noise in the tube



also, carefully inspect the mounts - look for leakage - look for distance between flanges

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[TheMirror]

[quote name='flash' date='Mar 16 2006, 03:03 PM']ok - do a couple of start-offs in 2nd gear (3rd too if you can) - if it does it in all gears, then you are likely at motor mounts or torque tube bearings



the next thing to do is get it on a lift, have someone in the car do the startoff thing while in the air, and listen for noise in the tube



also, carefully inspect the mounts - look for leakage - look for distance between flanges

[right][post="17451"]<{POST_SNAPBACK}>[/post][/right][/quote]



Great, thanks for the head's up! It'll be next week before I can get at the car again.



Best,

-Mirror

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