Ok here is what is going on I have a mild built 468bbc about 625hp I took it out a few times shifted fine then I took it out a week later got on it a few times shifted fine then I got on it one more time and I shifted 1st 2nd then I went to go into 3rd and it did not feel like it shifted and the rpms stayed at 6000rpm then I slowed down and got back into it and it felt like it shifted but it still was not going anywhere and rpms stayed at 6000. Heres the things I have tryed already yes the shift linkage is right the fluid is at the right level and the fluid still looks brand new very clean nice and red but I did just put the fluid in a month ago and drove the car 10 miles at most if that helps. Is the trans gone?????

 

Sounds like you hurt the direct clutch pack. Fairly comon in a stock th400 or one that was not built correctly.

 

well just went out yesterday and bought a coan th400 trans so as soon as i get the old one out i am going to take it apart and see what went wrong

 

The direct clutch accumulator in the valvebody likes to crack and bleed off pressure, replace the plastic with a alluminum one.

 

http://www.makcotransmissionparts.co...-400servo.html