how to repair an input shaft speed sensor circutit malfunction

it is a straight forward job , remove the connector on the passenger side by twisting it then the female side have an 8 mm bolt in the middle hold in it, loosen the bolt and pull the outer connector straight (no twisting at this time) .empty the oil in a bucket that can hold up to 7 quarts so you can measure the oil so you add the same amount later,.after remove the oil pan,and the remove 10 star blots holding the valve body.when it is out remove the electronic part on the top and replace it with a new one . remember to align the shifter when installing. no panic easy job reset your ECU codes

Mine has went out on me took it to my mechanic there telling me i need a new transmission is this true or not true