1982 Ski-Doo Shop Manual, Page 234Get this manual
SECTION 03 TRANSMISSION SUB-SECTION 08 (GEARBOX)
REMOVAL
Remove pulley guard and drive beltRemove seat backs and seats then remove plates to allow access to engine compartment Remove engine from vehicle Remove brake assembly and detach driven pulley supportRemove shifter mechanismRelease track tensionRemove suspension systemsDrain oil from chaincase (incorporated with frame)Remove end bearing housingsRemove drive axle then pull back gearbox assembly until it is possible to enter hand to remove the two (2) tensioners inside the housing between the track tunnelsNOTE: It is necessary to cut hole in fiberglass frame in order to be able to reach chain tensioner retaining bolts and nuts
Layshaft gear
Layshaft Shim(s) (if applicable)