Today I inspected my IMSB without removing it (2000 Boxster 5-speed, 115,500 Mi.). First, it is a dual row bearing and it looks perfect, turns smoothly and there is no looseness. I pulled the rear bearing seal and oil came out... I was surprised that it didn't smell burned and it looked relatively clean. The grease was totally gone.
At this point the plan is to change the seal on the IMS flange and put it back together. I watched the PCA videos with Jake Raby again and he explained the logic behind removing the seals to help lubricate the bearing. I feel confident with this procedure on this car at this time.
With the seal in place
With the seal removed
