[temerity]

Firstly . . . you have not stated if you have an auto or manual trans if it is an auto I would check for an internal leak between the TC seal )Torque Convertor)and the (Gearbox)GB, also the input shaft seal on the transmission that resides inside the TC (acces it by removing the TC)could also be the problem, as it is only a small o-ring on the input shaft.
If the trans is a manual 4or 5spd Try looking at your clutch for wear and glasing a good indicator, then the input shaft case seals.