Originally Posted by EricSilver

You are on borrowed time. Run to the dealer as fast as you can and order a new tumbler. When it fails for good, and it will, you are looking at an $800+ repair job.

I had that problem about three years ago, during which time the MB tech said, "the 89's are starting to go" referring to the tumblers. Almost $1,000 and five days later, it was fixed. Had I acted sooner, it would have been a DIY job for about $100.