I noticed that I was getting quite a bit of backlash between my main and pinion. Shims can loosen things up but how to tighten without pushing the clutch stack clear out of alignment? No way that I'm aware of. So I dropped the motor to take a look at things. Anyway it seems the answer is just short of 4 years and God knows how many crashes and gallons of fuel. Think I'll save this one as a good luck charm.