if my automatic t/a lt1 96 only goes into 1st gear and 2nd gear and just when its about to go into 3rd ..it revs up real high (4-5000 rpms) before it catch 3rd gear ..now keep in mind im only going about 30 miles per hr at the time it goes into 3rd gear ...then after that
3rd shift ..its just rev real high but wont change gears ...i put transmission fluid in it ..because it was extremely low..do i suppose to just keep driving until the fluid makes it way throughout the trans. or is it possibly something else going on

 

The clutches are probably toast. It may be time to start looking for a tranny or consider rebuilding yours.

 

You already posted this problem on this forum, and I moved it to Drivetrain. Please post only on the correct forum.