I am sorry I caught this post so late...
Did they replace the radiator when they replaced the transmission?
The only thing (within reason) that generally kills these transmissions is a failing radiator mixing coolant into the ATF via the heat exchanger built into the radiator.
Your model year is infamous for it.
Putting in a new transmission without replacing the radiator simply will destroy the new transmission.
If you paid a shop to replace the tranny they must have the professional knowledge to replace the raditor or at the very least bypass the ATF loop from the radiator.
Any aftermarket radiator as well as the newer OEMs radiators will not have this issue.
It was specific for the radiators put into the 05-10 model years with the 05+06 being the most vulnerable.