The oil pressure in my truck went down and the engine started knocking. The truck still runs, but it makes noise now.
The knocking noise is the piston rod bearings or the crankshaft main bearings. A failure of either of these will create a drop in oil pressure along with the knock. This internal engine failure will only get worse and will eventually seize the engine completely. If you need to have this taken care of, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the knocking noise and determine what repairs are needed.