What was found
(CAN) TAIL 833 CREW REJECTED THE TAKEOFF WHEN THE TORQUE INDICATION ON THE NR 2 ENG WENT TO ZERO BOTH ANALOG & DIGITAL. AFTER TALKING TO MX, THE CREW TRIED AGAIN & THEY DID ANOTHER REJECTED TAKEOFF. BOTH REJECTED TAKEOFFS WERE BELOW 80 KTS. ACFT REMOVED FOR THE LINE & START TROUBLESHOOTING. NR 2 ENG TORQUE INDICATOR & TORQUE SENSOR REPLACED & NO FIX. ALSO THE NR 2 ENG HARNESS REPLACED & NO FIX. ENG NR 1 & NR 2, TORQUE SIGNAL CONDITIONING UNIT & ELECTRONIC ENGINE CONTROL UNIT SWAP & STILL NO FIX. DURING TROUBLESHOOTING, IT WAS FOUND THAT WE HAVE STEADY SNAG WITH NR 2 ENG IN MAX & REVERSE, THE TORQUE RISE & SUDDENLY DROPS TO ZERO AT APPROX 50% OF TORQUE. DECISION WAS MADE TO REPLACE THE NR 2 ENG. INSPECTION WAS MADE ON REMOVED ENG & FOUND DAMAGE ON THE PROP SHAFT INNER PORTION & DAMAGE ALSO FOUND ON TORQUE SHAFT WITH METAL PART MISSING. THIS ENG WAS INSTALLED ON ACFT, THE 1 FEBRUARY 2010 REFERENCE WO 223552.