Team_Jake
Member
That's strange. I've had my lefty since 2011 and it was built with chromoly 30-spline output shafts front and rear. So upgraded output shafts were definitely an option.
From my understanding, the older 30-spline chromoly shafts didn’t have the ability to run oil through them, so there were instances where they would burn up and break if under larger/heavier loads. The new 30-spline shafts Marlin just came out with fixes that.