I would also look at the sprockets for "waving", the wear pattern that makes the teeth non symetrical, and look carefully at the chain for wear at the link axles.

Just because it was not appearing worn before does not necessarily mean it is not worn now.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.