Exact model info is #31AE6C0F022. Serial #1H129B40471.This is a used and recently purchased 8.5 HP 26 inch, two stage, self propelled, snow thrower by Yard, aka MTD of Cleveland Ohio. Color is Black (should that further define model or vintage. There is no power in any gear range to the right wheel. Is this likely a shear pin replacement situation. Please advise of likely costs involved to resolve. Does anyone have a manual?