My tranny is giving trouble

, there is a delay in shifting gears from park to reverse, neutral to drive, and when the car comes to a stop there is a delay there as well. A heavy jerk is usually felt after each delay. there is no delay in shifting up through the gears when the car is driving.
i changed the tranny, speed sensors even swapped out the brainbox of a same model accord. to see if that was causing the problem, nothing works.
Engine is a f20b SOHC.
any help would be appreciated.