Can I use Section 179 or I traded in my old extended cab truck (Ford F-150 extended cab) for a four door vehicle (RAV-4), to use primarily for Lyft and Uber ?

Yes, you qualify for a section 179 deduction provided you have enough income to allow for it.  

Go ahead and enter your vehicle purchase into TurboTax after you have entered all of your rideshare driving income information for this year and TurboTax will figure out whether you qualify for the 179 deduction at that point.  If you do the system will give you the option to take it.

@jctcooter