7. If the transmission shafts tend to come off with the left case, push them down into the right case while lifting the left case off.  Be sure all shafts except the crankshaft are not withdrawn more than 1/4" from the right case, or the shims could f all off the right ends of the shafts, making them hard to identify when reassembling the transmission. 8. Check inside the left case on the mounting bosses of the main shaft, lay shaft, shift drum, and kick starter shaft for shims which may stick to these bosses.  Remove them and install on their respective shafts.