What was found
BRAKE DIFF TEMP, LEVEL ONE ALERT CAME ON DURING CLIMB, TIRE NR 8 WHILE READING QRH IT BECAME A LEVEL TWO BRAKE OVERHEAT WITH A TEMP OF 640 DEGREES AT FL 370. DESCENDED TO FL240, SLOWED AND LOWERED THE GEAR IAW QRH. THE TEMP BEGAN TO DECREASE, BUT THE INDICATION WENT AWAY SHORTLY THEREAFTER. REMOVED AND REPLACED THE NR 8 BRAKE TEMP SENSOR IAW AMM 32-46-01-4. OPS CHECKED GOOD. ACFT OK FOR SERVICE.