What was found
DURING CLIMB, THE NR 1 ENGINE EGT REACHED 892 DEGREES CELSIUS. RETARDED THRUST, EGT DECREASED, BUT WAS STILL 50 DEGREES CELSIUS GREATER THAN NR 2 ENGINE. RETURNED TO MSP AND LANDED WITHOUT FURTHER EVENT. GROUND MAINTENANCE INSPECTED ENGINE AND FOUND LOWER VARIABLE BLEED VALVE FLEX DRIVE SHAFT END WORN. REPLACED FLEX SHAFT, AIRCRAFT RETURNED TO SERVICE.