I am working on a bike with an XTR e type derailluer, mountain triple. the middle chainring is missing a tooth, located behind the crank. when shifting between the middle and largest chainring, the chain gets jammed. it isnt always in the same spot, and it can be either while shifting down or up, and only under weight. The e type derailluer may be 1/2 mil too high, but other than that looks good, i am not even sure if i know how to adjust the e type closer to the rings. but i though that the broken tooth may be the real culprit.