A904-No first gear with a Turbo Action Valve Body

Sounds like it's stuck in 2nd gear. Does reverse work correctly? If so check the front band adjustment first. I can't imagine it tightening up on it's own but it's something to check. If the band adjustment checks ok it must be a stuck valve in the valve body. You didn't say but I assume this is a manual shift valve body?? If so it's highly modified from stock so I'm not sure what to tell you to look for. You'll just have to carefully take it apart and check for a stuck valve somewhere. If this is an automatic shift valve body I'd suspect a stuck governor. Maybe a piece of grit got in it and hung it up. Since you say the fluid condition was good I assume you didn't find much debris in the pan?