Yes maybe the previous owner used to spray diesel underneath the car , i havent got it done even once yet 
i got it changed from MIAN OIL CHANGE at QADRI CHOWK , i get all the lubricants for my car from here.
i'll post a pic for your ease . its not easy to access the gear oil level of cultus
hahaha . same here, i'm busy in my exams but still spent an hour with my ride today 