It's almost two years to the day since I got back my '78 6.9 from the repair shop where I had all five spheres replaced. This afternoon while driving home from work, the bounce has returned signaling the demise of one or more of those spheres. Bouncy bouncy is how I would best describe the ride home. Taking a poll of the reading audience: How long have you been able to run before having to replace these spheres? And what diagnostic steps should my repair guy take to diagnose which one or...