What was found
UPON DEPARTURE FROM YNG ON FLIGHT #3397, GEAR WOULD NOT RETRACT INTO UPLOCKED POSITION. QRH FOLLOWED AND FLIGHT WAS MADE TO DTW WITH THE GEAR DOWN. MAINTENANCE REMOVED AND REPLACED LANDING GEAR CONTROL BOX, PN D494-12-001, SN/ON 632/03-97. SN/OFF 677/08-98. PERFORMED OPS CHECKS IAW SAAB AMM CH. 32-01-05. ALL CHECKS GOOD.