Whirlpool AWZ541 T/D

Machine sometimes makes a squealing noise, particularly when turning anticlockwise. There is also a scuffing noise when stopping and starting. I have had the drum out and looked at the 4 roller wheels and 2 jockey wheels and all look OK but there were some deposits round the front track of the drum suggesting the drum had picked up bits off the surface of the wheels. I put a drop of 3 in one oil on all 6 spindles but this made no difference to the noise. Any advice much appreciated.
Phil