GMC M9500 1977: WHEELS:HUB

General Information

NHTSA Campaign ID Number: 77V172000

Make Model Year
GMC M9500 1977
Date Owners Notified Date Received by ODI Date Added to Database
1977-10-31 1977-10-12 1979-10-12

Production Dates: 1976-03-01 - 1977-06-01

Manufacturers Involved: General Motors, LLC

Component: WHEELS:HUB

Potential Number Of Units Affected: 685

Report Initiator: MFR MFR Report

Summary

THE FRONT AXLE ALUMINUM HUBS ON THE INVOLVED VEHICLES MAY CONTAIN A DEFICIENCY IN THE BARREL AREA BETWEEN THE INNER AND OUTER BEARINGS WHICH MAY RESULT IN CRACKS WHICH COULD EVENTUALLY LEAD TO HUB FAILURE.

Remedy

DEALER WILL INSPECT AND REPLACE FRONT AXLE ALUMINUM HUBS WITH STEEL HUBS, WITHOUT CHARGE TO OWNER.

Notes

VEHICLE DESCRIPTION: HEAVY TRUCKS EQUIPPED WITH FF931 FRONT AXLES AND MOTORWHEEL ALUMINUM FRONT HUBS.SYSTEM: WHEELS; ALUMINUM HUBS.CONSEQUENCES OF DEFECT: WHEN HUB FAILURE OCCURS, THE SEPARATED HUB IS RETAINEDON THE AXLE SPINDLE BY THE WHEEL BEARING ADJUSTING NUTS. CONTINUED VEHICLEOPERATION AFTER A HUB SEPARATION CAN RESULT IN 1' BRAKE ASSEMBLY LOCKUP ANDCONSEQUENT LOSS OF VEHICLE CONTROL, 2' EXCESSIVE HEAT GENERATION RESULTING FROMTHE BRAKE LINE TOUCHING THE BRAKE DRUM WHICH WILL CAUSE A TIRE BLOWOUT AND 3'PROGRESSIVE DAMAGE TO THE HUB WHICH WOULD ALLOW THE HUB, WHEEL, AND TIRE TOBECOME DISENGAGED FROM THE VEHICLE.NOTE: INITIAL HUB SEPARATION MAY BE ACCOMPANIED BY A DISTINCT SOUND AT THEMOMENT OF SEPARATION, ALONG WITH THUMPING OR WHEEL WOBBLE.