1985 Ski-Doo snowmobile Service Manual, Page 310Get this manual
Section 03 TRANSMISSION Sub-section 07 (CHAINCASE)
REMOVAL
To remove chaincase from vehicle, proceed as follows:
9, Cotter pin
Install new cotter pin
20, Chaincase cover
Remove and drain oil
30, Chaincase oil
Refill with chaincase oil 1200 ml7 floz)
Drive axle oil seal
Pry out from chaincase
12, 3,24, Sprocketschain
Remove from chaincase
26, Chaincase retaining bolts