P0175 (Turbine speed sensor malfunction) stuck in limp home mode (1st gear)

What is your question?

My baby has 61,500 miles on it, this is the first BIG problem I've ever had. I would like to do the work myself,(retired and plenty of time), if this is possible. Where is this sensor located? do I need to do anything special? or would I be better off taking it to a shop??