Hello, welcome to FixYa.
I'll start by saying this particular model of Maytag was built by Samsung as you may or may not already know.
The Sensor you are referring to is indeed the most common reason of the 3E error code...faulty hall sensor (also referred to as a RPS).
It is actually mounted on the back of the unit and it's function is to send the motion of the motor to the control board, when it fails the control senses an error, thus displaying the 3E.
To replace it will require you to remove the rotor and the stator from the back of the drum. The first step is to
**unplug the washer of course...safety first** Remove the back panel of the washer, this will reveal the rotor&stator assy (otherwise known as a motor) i.e. this is slightly different than yours, but essentially the same. Once this has been done, you will need to remove the large center bolt to remove the rotor. The rotor will resist being pulled as it is essentially a large magnet.
Once removed you will actually see the RPS (hall sensor) that you need to replace...though I'd suggest making sure the wire harness is seated properly as well as that can sometimes initiate the 3E. (sorry for the poor quality of the image).
Let me know how you manage or if anything isn't clear and I'll continue to try and help you move forward from there. Good luck.
Regards,
Macmarkus :)