1980 Ski-Doo Shop Manual, Page 274Get this manual
SECTION 05 SUB-SECTION 07 (CHAINCASE)
REMOVAL
Remove the suspension
Longer flange
NOTE: On the Blizzard 7500Blizzard 9500Super Sonic and Ultra Sonic disconnect the muffler and push it aside underneath the exhaust pipesRemove the chaincase cover and drain the oil
Slacken the end bearing housingPry out the drive axle oil seal from the chaincaseRelease chain tension then open the tab locks locking the sprocketsRemove the screwswasherssprockets and chainRemove bolts andor nuts securing the chaincase to the frame
Install the tab locks as illustratedInstall the screws and torque to 9.5 N'm (7 ft-Ibs)Bend the tab locks_ CAUTION: Lock tabs should be replaced if bent more than twiceIf in doubt, replace
INSPECTION
Visually inspect the chain for crackeddamaged or missing link rollersInspect for defective bearingsprockets