CHEVROLET OPTRA RETAINER PROBLEM

Friends good day ...
I have a problem with a minimum oil leak from the box, by the retentive of the left axis that is stuck to the box I already changed it 2 times and the drip is still there, I don't really know what is the problem that there is the leak. If the 2 retainers on both the left and the right have been installed correctly ... I do not know if it may be that the same axis to the rolling momet produces the damage because it has some type of twist or aboller. Please help me confirm this problem ... thanks

You should put the retain more inside if you can or something else out, if the axis has wear where it slips the retain (many kmts ..) always coincides in that channel and does not squeeze well there ... the fact is that it is not touching where it always does. Greetings!!