Sounds like could be the Torque convertor but either way you look at it the trans is going to have to come out. If you have over 100k on the trans then you need to think about getting a OE remanufactured trans which will come with a remanufactured torque convertor or a rebuilt trans. i personally like the ZF remanufactured trans as opposed to a rebuilt one. The remanufactured trans is more thoroughly addressed then many of the rebuilt. If I were to go the rebuilt route the only person/entity that I would trust for this is RHPHIL. He is a great board resource and does many of these transmissions The only problem is that he resides in the UK so too far to take advantage of.