rondv

1996 Civic LX 4-sp auto (70,xxx miles) seems to be having some transmission problems. Shifts hard especially when cold. Late, hard shift from 2nd - 3rd when cold. More bothersome is an intermitant refusal to go into 4rth gear lock-up. Sometimes works perfectly;sometimes just refused to enter lock-up.
Flushed tranny and replaced fluid with synthetic. Big improvment but still occassional refusal to enter lock-up at highway speeds. If "backing off" going down a hill it properly drops out of lock-up but is very stubborn in locking back up. Funny, if I put the brake on to take it out of lock-up fist, it will jump back in with no problems. I've been told it's the linear solenoid. I've been told it's the lock-up solenoid ; the engine load module ; all of the above and none of the above.
Anyone run into this problem or have any idea on a fix? Any help and/or ideas would be appreciated.