Our mechanic has told us we need a “new transmission pump”. The transmisson must be dropped to replace the pump. Cost is $ 1,900.

Is this coorect?

Likely yes.

Note this could be very cheap for a Mercedes or maybe a little high for a Ford Escort. You need to list the make/model of vehicle in order to get a better answer.

“Is this coorect?”

Is what correct ?
We don’t know what model-year, make, or model of your vehicle, we don’t know what symptoms you were experiencing, and we don’t know your mechanic (neighbor, certified in transmission repairs, etcetera).

Also, labor rates vary greatly from one locale to another.

You’ll need to provide much more detail. Fill in some blanks as mentioned above and tell us specifically what the symptoms were and how the mechanic diagnosed the transmission problem.