What was found
ON TAKEOFF, UNABLE TO RETRACT LANDING GEAR. PERFORMED COCKPIT OPERATING MANUAL (COM), NOSE STEERING WAS ACTIVE. CONTINUED FLIGHT TO DTW WITH GEAR IN DOWN POSITION. FLIGHT LANDED WITHOUT INCIDENT. MAINTENANCE JACKED AIRCRAFT AND FOUND NOSE STRUT CONTAMINATED WITH METAL FROM DISINTEGRATED BEARING. REPLACED LOWER SHOCK STRUT ASSEMBLY, OPERATIONAL CHECKED GEAR, RETRACT AND GROUND SHIFT FUNCTIONS NORMAL. GEAR OPERATION CHECKS GOOD.