TC feedback that loud sound was heard atfront DT A1 door when train doors opening. Staff (NEW) chec ked and confirmed A1 door spring out opening. ~~~~~ 3547 TC feedback that loud sound was heard at front DT A1 door when train doors opening. Staff (NEW) confirmed A1 door spring out opening. T-218-3547-A1 door opening and closing ok. Opening soft bang noise heard. CE feedback.  3547 A1 door when opening, a gear clicking sound was heard. OPS 20 raised to follow-up.  Chan SW/Hanafi 44067 To continue rectification.     3547 A1 door found roller operation not smooth. Replaced door roller & door cyclic test 20x - OK.  Selvan/Lee PT/Alcus 44067