I bought a TCI manual valvebody for my TH400, reversed shift pattern. Before I bought it I asked at the store if it is possible to do the swap with the trans installed and the answer was Yes You Can. I have asked several so called "experts" before and they all saied the same, You can do it without dropping the trans. However when I opened the box and start reading the instructions it says remove the transmission... and there are some mods to be made inside the trans. Impossible to do without dropping it. But are the mods really important? How will my trans perform if I skip the internal mods and just drive the thing?