My CL350 has a cracked tach drive housing so I need to replace it. Has anyone done this job, and can give me some pointers. I think the motor needs to be rotated to take tension off the cam, etc. ??? My concern is: does the cam tend to get stuck in the housing? If so, could I accidentally score the cam when pulling it off? I would like to know all the warnings BEFORE I attempt. Thanks a lot.