Allright guys I'm a carpenter don't know to much about trucks still learning. Right now I got 3.73 I want to upgrade to 4.10s. What all do I need to buy? Is that front and back? I just don't know lol help greatly appreciated thanks :)

 

First, why are you going to 4.10s ?

My thoughts on parts...
Gears of course both frt and rear.
Rebuild kits both frt and rear.

While you are at it and if the truck has high milage on it since last brake job consider brakes.
While everything is apart mights well.

4.10s will raise the rpms of the engine in every gear.
First will be lower and have more power and forth and fifth will run higher rpms at any given speed and may or may not burn more gas, overall more pulling power.

Luck with that.