hi just serviced my td5 and i found a small drip coming from between the bellhousing and engine.on the bottom of the bellhousing nearest the block thier is a plug with a square inset ,if i remove this will this drain out any oil residue in the bellhousing which has collected over time as it doesnt say on the cd rom what this plug is for any help or suggestions, i know that the oil is probably from the crank oil seal but i will have to keep an eye on my oil levels for now just want to sort the leek first cheers gary