I read something before about the driveline on the LS1's making noise or vibrating. Just bought a 98 SS automatic (don't laugh). When I hit 55 or better there is a harmonic vibration about every second intervals. If it's the drive shaft what can I do to fix it or replace it with?

 

SEE IF THIS HELPS



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Correcting Driveline Vibration - RWD and 4WD
Diagnosis will be much easier once you have identified a vibration as first-order of driveline rotation during the road test. Then identify the exact area that the vibration is coming from and take proper action.

In most cases, vibration may be reproduced in the stall. In the stall the vibration may be better or worse than that experienced during the road test.

The objective is to reduce the vibration to the lowest point possible in the stall, than evaluate the results on a road test. Many times, a vibration you were able to reduce drastically in the stall will be completely eliminated on the road.

The cause of first-order drive line vibration is usually excessive runout or an imbalanced component.

The following procedure offers a systematic process of elimination in order to determine which component is at fault:

Raise the vehicle to curb height. Support the vehicle on a hoist or heavy stands. Refer to Lifting and Jacking the Vehicle
Remove the rear tire/wheel assemblies. Refer to Wheel Removal
Inspect the propeller shaft. The propeller shaft should be free of undercoating before continuing this diagnosis.
Inspect the propeller shaft or U-joints for any obvious dents or damage. Dents or damage will contribute to first-order driveline vibrations.
Start the engine.
Place the transmission in gear.
Run the vehicle up to the speed at which the vibration was most severe. Do not step on the brake while the brake drums are removed.
Note the vibration present, and at what speed.
If the vibration is not present, refer to Driveline Vibration Analysis .
If the vibration is present, determine which end of the driveshaft is vibrating the most. Hold your hand against the pinion nose and the transmission tailshaft, or hold an EVA vibration sensor up to each component.
If the vehicle is equipped with a two-piece propeller shaft, inspect the center support bearing for vibration.
If the transmission tail is vibrating, touch the transmission crossmember under the transmission mount. If there is no vibration on the crossmember, then the transmission mount is working properly.
Note which end of the driveshaft is the worst, and how severe the vibration is. The inspection will be a reference by which to judge future progress.
Helpful Hints
Do not fill the propeller shaft with foam, oil, or any other substance in order to correct a vibration. Filling the propeller shaft is only effective in reducing an unrelated condition called Torsional Rattle. Filling the propeller shaft should only be done in strict adherence to the procedure outlined in corporate bulletins that address Torsional Rattle. Failure to follow the correct procedure will induce a vibration and/or affect the structural integrity of the propeller shaft. The propeller shaft will then have to be replaced.

Propeller Shaft Runout
A propeller shaft or pinion (companion) flange with excessive runout causes first-order driveline vibrations. Use the following procedure in order to measure runout of the propeller shaft (2). The tolerances are critical for smooth operation of the driveline.

• Remove excess corrosion of the propeller shaft surface before checking runout. Also inspect for damage and dents. Replace dented propeller shafts. Remove any undercoating from the propeller shaft before proceeding.

• The measurement procedure that follows applies to all one-piece and two-piece propeller shaft assemblies. The splined end (1)of a propeller shaft is critical to the smooth operation of a two-piece propeller shaft. When checking stub-shaft runout, ensure that the dial indicator readings are accurate.

Measuring Propeller Shaft Runout

Tools Required


• J 8001 Dial Indicator Set

• J 7872 Magnetic Base Dial

 

Well, if nothing else you must win the price for longest post in history!!!

Why not start by checking to see if the wheels are balanced. Then check the transmission crossbrace mount, then move out to worries about the drive shaft.

 

I remember something about trans mount somewhere in that bulletin.

By the way, that is a GM bulletin for a known issue with drive shaft ballence in 96-02 f bodies.
Of course the easier way to do it, would be to take the driveshaft to a shop that can check the ballence of it.

 

Yeah, but I'd start there myself. Sso many people hear about that and think they have it, maybe he does, but it costs little to get the tires balanced and it eliminates a probably cause before you go spending money.

 

Is GM still using the two piece shaft or did they switch back to the one piece? The 2 piece was a very, very bad design. All the ones I've seen used a carrier bearing w/a c/v joint in the middle of the shaft, and if any of you have ever cut one open you'll find that it's built with another smaller dia. tube inside the main tube. All these design flaws together is why they start to vibrate after awhile. You can't balance them because the inner tube breaks loose of the rubber supporting it. At that point you have two options: buy a new shaft from GM, or for less money have a one piece shaft made. making a one piece is the best plan, but requires some modification to the torque brace. As for diagnsis, I gotta side w/ Lee, Check mounts, ujoints, shocks, bushings, and tires. I'd say if you have a two piece shaft w/ 50k or more on it replace it.

 

The camaros use a one piece, about the only GM product to use a two piece is a long bed truck. Where the distance inbetween the trans. and axle is too great for a piece.

 

All I can tell you is that I have taken a two peice out of an F body, may have been a Firebird, and built a one piece and installed it.

 

IN my two vibration expeirences it was the tranny mount both times, either that or a new one absorbed the vibration so I did not feel it anymore. Cheers..................

 

Some of the 4th gen 6 cylinder Camaros were built with two piece driveshafts. Why, I don't know.