Honda Accord: Transmission problem

My 2nd week with my power of dreams, everything is working great except the transmission is giving problem.

The Symptoms before ATF change:

1. Shifting N to D, N to R takes longer time to engage into gear, more than 3 seconds
2. Shifting from 1 to 2 slow. it gives a hard shift when I rev on the engine.
3. No burn smell in the ATF - no sign of burn clutch pad though. (this is an important factor to determine if it is an external or internal gearbox problem)

The Symptoms after ATF change:

1.  N to R gear engage normally.
2.  N to D gear still get 2 seconds delay during cold start. It is norm after the warm up.
3. Shifting from 1 to 2 is smooth when I rev the car below 3k
4. Shifting from 1 to 2 is hard when I rev the car over 3k
5. No burn smell in ATF

Possible Causes:
1. Vehicle Speed sensor - written off
2. Transmission Solenoid - written off

3. Worn clutch pad - can't write off entirely - no burn smell from ATF though
4. Dirty ATF - abuse from the previous owner with delay ATF change

The fix:
1.Change 3.5 liter of ATF

The cost:
1. 3.5 liter of Honda ATF Z1 - MYR84 (MYR24 per liter)
2. labor charge - MYR15