Code P0732 for gear ratio in 2nd

Hello
I had the vehicle towed to the local dodge dealership because it had gone into limp mode.
I was told by dealer mechanic
Would not shift into drive or reverse.
They checked the fluid and found it was overfull from pump/torque converter not picking it up.
Checked for codes and it has code P0732 for incorrect gear radio in 2nd.
Particular code cannot be diagnosed due to transmission losing prime.
I had it towed back home when I was told it would cost roughly $5500 for transmission and torque converter replacement.
It shifts into drive and reverse but seems to lose engine power after approximately.25 mile and goes into limp mode.
I guess I'm asking for a second opinion because it seems like I'm missing something small that's causing the problem.