Cadillac Repair: input/turbine speed sensor, turbine speed, cadillac sedan deville

Question
got 1996 cadillac sedan deville 4.6 i failed emissions because of an input/turbine speed sensor readout a mechanic said it really has nothing to do with emissions but illinois will fail it anyway. went to a few repair shops 1 said its in the trans the other which was AAMCO TRANS the popular chain of trans repair they said it was external and didnt have to go in the trans, so which is it? TAKE OUT TRANS OR NOT TAKE OUT TRANS

Answer
it is internal and some inventive technicians like me know how to split the trans from the engine and manipulate the engine and trans just enough so that you can get your hand inside to replace the sensor.

Factory service manual say's to pull the trans.