The float *must* move freely within its chamber and be mechanically connected to the arm that moves the fuel level sending unit's resistor. Getting the float upside down won't usually prevent installation, but it will render the fuel gauge useless.
Here's how to ensure correct installation:
1. Visual Inspection (before installation): Carefully examine the fuel pump assembly *before* you install it. Look for how the float arm is connected to the fuel level sending unit. The float should swing freely based on the movement of the arm.
2. Orientation is Determined by the Arm: The critical point is that the float's movement should correctly actuate the fuel level sending unit. If the float is positioned so that when the fuel level rises, the arm moves correctly, then it's oriented correctly. If it moves the opposite way, the gauge will read backward.
3. Test After Installation: The best way to check is after installation. After refilling the tank, check the fuel gauge. If the gauge shows empty when the tank is full, or vice-versa, you know the float is installed backward. You'll need to remove and correct the float's orientation.
4. Reference the Assembly Diagram: A shop manual or online parts diagram for your specific 1996 Dodge Ram 1500 fuel pump would show the correct orientation of the float and arm. This is your best resource.
In short, don't focus on an absolute "right side up" for the float itself, but on whether it correctly interacts with the fuel level sending unit arm. The gauge will tell you if it is properly connected.
