Happened about 4x times on my truck. What could be the cause?
Overspeeding? i don't think so.
no visible "canal" marks on the shaft
no nicks on the housing.
or maybe too much internal blow-by pressure?
This last time i put RTV silicone on the seal's outer lip for additional grip on the housing somehow.
It's too costly also replacing the t-belts everytime the seal jumps out.