How to replace a Fuel Filter on a Duramax.
To get you familiar with the Fuel Filter it is located underneath the hood near the firewall on the passenger side on the engine.
The tools needed to change out the d-max fuel filter using the side approach are a panel clip remover, a Water In Fuel sensor wrench (or channel locks), a 1/2 inch Nut driver, and I use 2-stroke oil to lube up the o-rings.
Starting off pop the hood, and then grab a seat and sit by your passenger side tire looking at the fender well.
Now using a the panel clip remover, you want to remove the pins that are holding the inner fender well liner to the truck. (can be easily done with the right tool, I have seen one of these at oriellys)
Now with all the pins remove and all the wire harnesses pulled out of the liner you can set the liner aside.
Now you can have a good view of the Fuel Filter from where the passenger side.
Now disconnect the WIF connector and let it hang.
Now you can unscrew the fuel filter and remove it. you might be able to do it with your hands if you are strong enough, if not u can use a strap wrench which can be found at any auto parts store.