I’ve got an 07 650i. I have a leak on the seal from the drive shaft to the engine. My drive shaft would not compress so I had to unbolt the rear diff to get it out of the engine. Since I’ve got it apart I wanted to replace the seal from the back of the drive shaft to the diff. My protis that the drive shaft won’t pull out of the diff. Should it just yank out or is there some type of retainer holding it in?