Astro Van M L4-151 2.5L (1985)
Drive/Propeller Shaft: Technical Service Bulletins
Drivetrain - Driveline Vibration & Noise Service Tool
Number:
92-190-4A
Section:
4A
Date:
May 1992
Corporate Bulletin No.: 260102R
ASE No.: A4
Subject:
DRIVELINE VIBRATION AND NOISE
Model and Year:
1985-92 M VANS
1990-92 L VANS
Various concerns related to vehicle vibration in 1985-1992 M/L vans have beesn studied and analyzed. Contributors to vibration can COme from the
engine, driveline, or wheel/tire systems which makes an accurate diagnosis difficult.
To aid the service technician with a systematic approach to diagnosis and correction, GM service worked with Kent Moore to develop and release the
Electronic Vibration Analyzer (EVA) (J 38792). By using EVA on a road test, the technician now has the ability to use the frequency of the vibration to
identify the source of the vibration. This tool, along with a complete understanding of the STG Vibration Correction booklet 13002.02 dated August
1990, is necessary in determining the cause and correction of vibration conditions in a vehicle. The EVA tool is available through Chevrolet Motor
Division's Tool Loaner Program as outlined in R.W. Starr's letter to all dealers dated January 24, 1992, Subject: Chevrolet Service Tool Loaner Pilot
Program, the procedure of which is attached. You may also call Kent Moore's toll free number (1-800-345- 2233) for complete details. The tool is
shipped on consignment with an instruction manual, STG Vibration Correction Booklet and Tire Rotational Order Charts.
GM service has made available a program for the dealers to address disturbances by installing "qualified components" into a problem vehicle. These
qualified parts are:
a.
Tires
b.
Front propshaft (L vans)
c.
Rear propshafts (M/L vans)
d.
Tuned damper, rear axle pinion nose