I am really confused and looking for some pointers.

Details of my vehicle: 2002 TL-S with transmission replaced by dealer at 172k, current odo reading 238k

Last week on Thu, I was driving on the highway when I had to speed up a little from 100kmh to 120kms really quickly to change lane, so I hit the gas a bit (heard the VTEC kick in) and changed the lane, after about 5 mins, the engine light came up with the Traction Control light in the Exclamation Mark.

I took the car to a dealer who did the diagnosis (basically read the code) and told me the code is related to transmission (clutch) and the transmission needs replacement, he reset the code so the lights went off.

My gears are all shifting fine, I just feel that the car is less power now (feels like 4 cylinder car instead of 6 when I push it)...when I said to the dealer, he said it might be the torque converter. (I don't know if me thinking the car is less power is just psychological now since I have started to take is easy on the car after this incident)

My question is that I am not having any issues with the gears shifting incorrectly, could that be a computer error? or how sure can I be that it's the tranny? Since the incident I have driven about 500kms and still don't feel any issues. Should I look for a replacement now if drive until I get the light again and it fails?