עפ"י האתר הזה:
http://www.thepopularmechanic.com/PorscheIMSOptions.html
נזילת השמן היא הסיבה לקריסת המיסב:
The Cause of the IMS Failure
According to the class action lawsuit, the signal row bearings have been deemed defective and yes, but that is really only partly true. The cause of IMS failure has been accepted by most independent Porsche specialists to be due to oil leaking past the outer seal into the original IMS bearing, washing away the permanent grease leaving the bearings susceptible to heat and friction. How does this happen? High levels of acid in the oil due to extended oil changes compromise the seals. But this happens in both single and double row bearings. Not intended to strike unnecessary fear into anyone, but the only difference between the different types of bearings is the design, not the materials. If the seals get compromised in the signal row, they also get compromise in the double row. So, then what is the answer? There are really two main approaches: maintenance or a permanent fix.