My 1966 dart race car.

A body said
recognized the solenoid and the support plate where the servo area is. The old ones didn't have that would would literally balloon the spacer plate in that area. Sounds like you've got a "top shelf" 904 now. If I were rainbow chasing I'd probably look into it.... but to be honest I would be at least 5K if not a little more to make the change..... or one that would live anyways :). curious.... did something "shake" when you changed your trans? Why do you think it's the trans and not the driveline?

Here is how it went. I had what I thought was 904 trans but it had six bolts for the rear support so this turned out to be a 999 trans or a 1989 trans. This is where I got the low first gear from it also has a better sprague than a regular 904. So everything was right in the world till I shifted two second gear and stripped out the output gears. So when I called A&A trans to get a billet first gear I also asked about the HD output shaft. He said it is bullet proof so i bought it also. Now this is where things get weird. Now depending on who you ask you will get a different story. but the HD shaft will not work with my 999 trans and I did not find that out till I was putting it together. So then I call them and ask whats up why will this not work. Now I need a different Case because a 1989 case "with six support bolts" is different. So I get a different case a 1975 yippy it all fits but now I have a different problem. I have a ticking time bomb in the rear of the trans called a "Stock Sprague." So now I buy the 30 element one. I install it and put all the parts together, it all fits, the sun is shining again and I can move the car under its own power again. So I get in it and drive it around the block a few times to warm it up. Bring it back home check fluids and now it time for a burn out. I wet the street get in my happy seat, start in second feel a little vibration, shift to high gear feel major vibrations. I pull the car into garage and back on the stands it goes. First check driveshaft, pull it out and have it checked, it's good. Second check wheels, pull them off they check perfect. Third check rear end, pull it out, everything perfect. Hmmmmm maybe engine, pull off flex plate put on fly wheel, bolt on standard shift bell housing, hook up starter, with the push of s button I find out engine is good. So ONLY thing left is trans. So I called A&A pulled the trans apart sent them every part i bought from them and told them don't sent it back till its good. So to answer your question "Why do you think it's the trans and not the driveline?" because I checked it ha ha ha.