This Preliminary Information communication provides information to the technician on the steps need to diagnose and repair vehicles that may have stalling shudder and/or hard shifting into 1st gear or reverse vibration on launch (with excessive crankshaft end play). Technician will test to determine if the crank shaft end play is within specification 0.0015?0.0086 inch. If end play is found to be out of specification, remove engine and inspect for possible crankshaft thrust bearing and/or crankshaft for wear. Inspect thrust bearing for wear on one side and crankshaft on that "mating" surface. If the thrust bearing has three vertical channels worn off replace connecting rod bearings, main bearings, thrust bearing and crankshaft. If working on a Corvette the oil tank with lines and oil cooler are both required to be replaced if equipped
