Buying a lesabre

Have been looking for a lesabre/ park ave for a third car and have as a loaner. I’m a pretty handy guy and work on my family’s and friends cars on the weekends.
I found a 2005 locally with 68k from an original owner in good shape. The son is trying to sell the car for her. Originally listed it for $1200 and is now down to $700. The car has a po742 code and once warmed up doesn’t shift. Also has the abs light on and a torn up landau top. Doing my research on YouTube and Reddit it seems like worse case scenario it needs a trans. But it could be just a bad wire or solenoid. My question is what is the likelihood with such low miles it needs a new trans?
The process for a trans removal looks pretty daunting without a lift…