Randy, Stop! no need to shim. The adjustment is that one phillips head screw you see in the picture at top right. Up and down adjuster screw.
They seem to miss the detailed set-up at the assembly. They just do not check things very well IMO.
Hope I saved you some work.
Garrick
Most atv utv i recommend 10w40 oil, period, but make sure it is JASCO MA2 for wet clutches, motorcycle oil.
U can use regular oil but it will burn easy cause of wet clutch and glaze the clutch, causing slippage.
Welcome and cheers from the North
That's sort of a confusing answer because of the way hisun terminology works.
The engine & the wet clutch & the high/low/reverse gears (which is what we traditionally term a "transmission") all share oil.
The rear differential has its own oil, but it isn't a "transmission" except in hisuns terminology. They also use the term "final drive" or something like that in some literature.