Bad tranny In Acura 4 cyl.

[BlackBII]

My buddies little sis has an Acura 4 cyl. Not sure hat model, like a '98 front wheel drive 4 banger, anyway she says she needs a new tranny (auto), the motor will rev to 4 grand before the car creeps anywhere, the fluid is good, a little dark but still good, new tranny? She has one in the trunk from the guy she bought it from