Bison, are you referring to the center section endplay (.006" to .008" per the CK manual) or the clearance between the direct clutch assembly backing plate and the snapring (.030" to .065")?
I assume the rear and forward section endplays are just as important, but the center section endplay would have the most affect on the direct drum, correct?
From what I can see, and I'm no expert, the part that failed held the snapring which holds the direct clutches in place against the apply pressure. The directs in this trans are not dual feed, which would have much more apply pressure. I found no other threads on this forum where this happened to anyone else, so I assume it's very rare and if the endplay is correct, I shouldn't worry about it happening again after dual feeding the trans. Although, with all the parts I've broken, I haven't burned any clutches...so maybe I'm not trying hard enough.
