Due to problems with this part in Set 8043 - Motorized Excavator, it was internally redesigned in the beginning of Sept-2010.
There are no visible external differences between old and new parts, also the part number stayed the same.
However, old and new parts are reported to have production codes stamped in the bottom - near the orange axle hole - which are supposed to indicate production week and year, e.g. 33x8, 35x9, 17x0, 36x0 etc., where the first two digits should indicate the week and the last digit should indicate the last digit of the year.
Parts having production codes 36x0 or later are supposed to be of the redesigned type.