It at the bottom of the gearbox, at the back. 8mm Allan Key. Should take about 1.75 lires of oil. Fiat Recommend ZC 75. Just one to check first though. Just diconnect the gear linkage cables at the rear of the gear box. They are just on ball joints, just pry them off and see if gear lever is nice and free, If so, sounds to be in the box, if still stiff sounds like gear linkage cables ceased.