If it is original the code in the door jam will tell you. Otherwise you will have to give us more info. Auto/manual, OD? If it is an auto, the there are prety much 3 options. Most likely an AOD, EAOD, or C6. I don't think it would be a C4. If no OD then it is a C6. If it has push button OD then it would be an EAOD. If it has OD and no way to keep it in 2 and the the selector reads PRN(D)D1 then it is likely an AOD. Some guys on here can also tell you by the bolt pattern on the pan. Hope this helps!