Hard shifting when car is cold?

[JEDI]

2005 Mazda3 AT, 160k miles

for the past couple of weeks, my transmission is shifting hard when i just start my car.

ie:
i'm at the 1st stop sign at my house. coast is clear and i hit the gas like i normally do, and i feel a hard shift. speed limit = 35mph

10min later i'm on the main road at a red light. it turns green, and i gun it. speed limit = 55mph. i dont feel any hard shifting.

should i be concerned about hard shifting when the car is cold?

 

[satyajitmenon]

When was the last time you changed your transmission fluid?

 

[JEDI]

When was the last time you changed your transmission fluid?

60k and 120k miles.

but the manual doesnt say change transmission fluid ever.
just coolant (and of course oil change)

 

[wirednuts]

you might try slapping a new valve body on that tranny- its probably just wearing out, or leaking a little internally... itll have solenoids and new check valves on it too, that might be sticking when cold.

do a bit of reading before you do it, but most newer valve bodies are easy to replace. they only cost around $200 reman too.