This paper presents the effect of balance gear on a reciprocating engine which drive the crude oil transfer pump that had experienced vibration at one of the offshore platform in Malaysia. Based on this case, it is imperative to understand more on the reciprocating engine vibration behavior especially those related to the balance gear positioning. The balance gear is a critical component that must be fitted right at the first installation. Due to the rarity of requirement for balance gear adjustments, there are gaps in term of experience and exposure of the operators with regards to the maintenance of this component. Hence, this paper addresses the gap.