I just bought a '78 diesel cruiser with a 4 speed and after about a week of normal driving all of the sudden the clutch doesn't work. Within a few hours it went from working fine to it being hard to change gears to now you can easily press the clutch to the floor with no resistance and it won't go into gear. It also looks like there may be a bit of transmission fluid under the truck, but not sure. I can't find the tranny dipstick or fill tube. I know nothing about these things, only had it for a week. Help!