GMC chervolet camaro 1999 Service Manual page 62

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General Information
Correcting Vibration at the Transmission
Tail shaft
First-order driveline vibrations that originate at the
transmission end of the propeller shaft are rare. If the
tailshaft of the transmission is vibrating, inspect the
tailshaft housing bushing for wear or damage. A leaky
transmission tailshaft oil seal indicates bushing
problems.
Feel for vibration at the crossmember underneath the
transmission mount. If there is no vibration, the
transmission mount is functioning properly by isolating
the vibration from the structure of the vehicle. The
transmission mount is therefore probably not the cause
of the vibration.
Use the following procedure if you can feel vibration
on the crossmember and the tailshaft bushing,
and if the transmission output is normal:
182281
1 . Measure the propeller shaft runout. If the runout is
excessive, replace the shaft with one that has
acceptable runout. Alternatively, sublet the shaft
to a reputable independent· service shop in
order to have the shaft rebalanced and the runout
corrected. · ·
2. Test drive the vehicle. If the vibration is still
unacceptable, balance the shaft on the vehicle.
Refer to Rear Drivel.ine System Balance.
Vibration Diagnosis and Correction 0-59
Correcting Vibration at the Center Support
Bearing
182285
These guidelines apply to the two-piece propeller shaft
only. First-order driveline vibrations that occur mainly
at the center support bearing are usually the result
of excessive runout at the stub (splined) shaft.
Unlike other first-order driveline vibrations, these
vibrations can appear at unusually low speeds
of 40 km/h (25 mph) and up. ·
Perform the following procedure. in order to correct this
type of vibration:
1. Mark the position of the rear propeller shaft at
both ends for proper reassembly.
2. Remove the rear propeller shaft from the vehicle.
3. Measure the runout of the stub shaft splines (3)
approximately 12.7 mm (0.5 in) from the end.
4. Replace the shaft if the runout exceeds the
tolerances.
Stub shaft/spline runout 0.076 mm (0.003 in).
Correcting the stub shaft/spline runout will usually
eliminate the vibration. If some residual vibration is still
present, perform a road test on the vehicle. Determine
if an on-vehicle system balance of the driveline is
necessary.