I need to replace my crankshaft sensor, how do i do this?My transmission is jerking on my 04 Maxima and after researching it seem that I need to replace this.

Pull the Diagnostic Trouble Code(s), if any, from the on-board computer and let that be your guide on where to begin. If you aren't familiar with that process, go to Autozone, where they will pull the code(s) for you for free. Other parts houses may do it for free or a nominal fee. The code will provide your starting point. Your diagnosis to date appears doubtful as the true cause of your issues.

Look for a leak in the hoses between the PCV valve in the crankcase and the intake on the motor. A vacuum leak of this type can cause a jerkiness (runs rough) and will make the transmission seem to be malfunctioning because the motor is trying to correct for incorrect air-fuel ratio. Check to see if there are soft squishy or very oily spots on those hoses (would indicate a hole at that position).

The crank sensor is for engine cylinder recognition or position.

Go back to your studying

You never replace any part or sensor based on a code or a guess.

You need to be familar with the system your working on, and test first,then replace, if you have the knowledge to do so.

You need to separate Trans Issues from Drivability Issues.