There have been two types of Chrysler Fuel Pumps used on the vehicles that have rolled off of the assembly lines. The first type used by Chrysler was the mechanical fuel pump. The second type was an electric fuel pump which is what is mainly used today.
The mechanical fuel pumps used suction to draw the fuel forward from the fuel tank so the carburetors could be supplied with this fossil fuel. It has a polymer diaphragm in it which in time would have a rupture causing the pump to not longer be able to create the necessary vacuum to draw the fuel from the tank. The fuel delivered by this mechanical pump varied in pressure and volume but that did not affect the needs of the carburetors that were used.
Chrysler fuel pumps are used today because of the precision in the amount of volume they can deliver along with a constant level of pressure that can be maintained in the fuel system by them. This is now a requirement by the fuel injection systems being installed on all Chrysler models roiling off the assembly line. These electric fuel pumps are now located in the fuel tank instead of on the engine like the older style mechanical ones were. This makes it possible to push the fuel forward and regulate the pressure more accurately.
Because the newer style of fuel pumps utilizes an electric motor, they will tend to wear out, just not as often as the older style with the polymer diaphragm in them. With the electric variety, the fuel system on your Chrysler is now pressurized once the ignition key is turned on. The older style had to have the engine running before pressure could be built up in it.