What was found
IN ROTATION ON TAKE OFF, HEARD A LOUD THUMP WHICH SOUNDED LIKE IT CAME FROM RT OF AIRCRAFT. LEFT THE MLG DOWN, BELIEVED A MLG TIRE BLOWN. DID A LOW APPROACH BACK AT AIRPORT & TOWER SAID MLG & TIRES APPEAR NORMAL. RETURNED & MADE A NORMAL LANDING. EVERYTHING APPEARED NORMAL BACK AT RAMP. WAS A GREATER THAN NORMAL NLG WHEEL VIBRATION DURING TAKEOFF. PERFORMED GVI OF ACFT & MLG. CHECKED NLG TORQUE LINKS, & TIRES FOR OUT OF ROUND. NO DEFECTS NOTED, FOUND EXCESSIVE NOSE WHEEL SPIN. PERFORMED NOSE WHEEL RETORQUE IAW AMM 32-42-01. COMPLIED WITH BORESCOPE INSPECTION OF RT ENG IAW WO FS73817 / 34997. ENG FAILED INSP & REQUIRES REPLACEMENT. ENG REPLACED IAW WO FS73817 /34997, ALL ENG RUNS LEAK & OPS CHECKS GOOD.