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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1700 (Vibration Symptoms Diagnosis And Correction) >> Diagnostic Information and Procedures >> Component Rotational Speed Calculation >> Propeller Shaft Rotational Speed Calculation

Propeller Shaft Rotational Speed Calculation

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Determine the first order rotational speed of the propeller shaft(s) in revolutions per second (Hz), based on the first-order rotational speed of the tire/wheel assemblies and the drive axle(s) (final drive) ratio(s).

    12 Hz X 3.42 drive axle (final drive) ratio = 41.04 Hz (rounded to 41 Hz) first-order propeller shaft rotation related

  2. Compare the rotational speed of the propeller shaft(s) at the specific vehicle speed at which the disturbance occurs, to the dominant frequency recorded on the J 38792-A  during testing. See Special Tools and Equipment . If the frequencies match, then a first-order disturbance related to the rotation of the propeller shaft is present.

    If the frequencies do not match, then the disturbance may be related to the second-order of propeller shaft rotation.

  3. To compute a second order propeller shaft rotation related disturbance, multiply the first order rotational speed of the propeller shaft at the specific vehicle speed at which the disturbance occurs, by the order number of 2:

    41 Hz X 2 (for second order) = 82 Hz second-order propeller shaft rotation related

    If the computation matches the frequency of the disturbance, a disturbance relating to the second-order rotation of the propeller shaft is present.