Subject: Positraction Chatter
Model and Year: NA
Source: Chevrolet Dealer Service Technical Bulletin
Bulletin Number: 78-T-5, Section IV
Date: Jan., 1978
TO: ALL CHEVROLET DEALERS
In some cases after extended expressway driving in warm ambients, a slip stick condition (chatter) occurs in the clutch plates of positraction axles during tight turns. Rubbing or moaning noises may accompany the chatter noise. Chattering conditions may be corrected by flushing the rear axle per the following procedure. If chatter recurs at a later mileage, add additive only.
NOTE: If it is not possible to perform Step #7, owner should be advised that it will require a minimum of 25 miles of normal driving to thoroughly work new lubricant into the clutch pack.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
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Article ID: 709
Created: August 2, 2014
Last Updated: August 2, 2014
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/1970-corvette-service-bulletin-positraction-chatter-709.html