Thanks to mightyjebus, I managed to disassemble the gas block and fixed the cocking lever. Tried to pull out the gearbox, like you told - did not succeed though, just managed to pull out it further, but the nozzle and the wires hold it, afraid to break nozzle - everything is so tight.. Well, may be will try later, as my main concern was cocking lever. Thank you again!
P.S. Mine chronoed 133-134 m/s with I'm not sure what kind of bbs and 136-139 m/s with bbs came in the package