Ok, so not sure if this issue has been addressed before, but my '06 Accord 2.4 AT has been really messed up the past couple of days. When I take off from a complete stop it shifts quickly and pretty hard under normal acceleration. It also doesn't wanna shift into 3rd at all sometimes. I'm pretty sure there is a leaking line near the bottom of the radiator but I'm not sure which one it is. There is one that comes from the back of the transmission to the radiator and one from the front, both with banjo fittings. Not sure if these are the cause though. Also my CEL is on but haven't been able to check it yet.

 

There are two lines from the transmission that connect to the radiator to cool down the transmission fluid. One line is the send the other is the return.

Have you checked your transmission fluid level? There are instructions in your owner's manual on how to check it.

 

CEL will provide best clue to your trans problem. Go to Autozone, O'Riellys, etc for free code extraction. Write down the code/s and post them (Pnnnn) here for further help.

good luck