I got a th400 trans and Ive been told that the kickdown is activated either by vacuum or by an electrical switch. How can I tell which one I have. There is a tube which runs from the manifold to the trans, but there is also a little tab that sticks out on the drivers side right next to the speedo cable. When I floor it it doesnt kick down. which one do I have and if its the vacuum type how do I fix this problem. I know its alot but any help would be greatly appreciated! Thanks in advance!