My truck has been making a knocking noise upon acceleration. Today the knocking is constant and louder. What could this be? Pistons? Oil sludge? New motor?
The 3.7 is notorious for having a rocker arm fall off and or lifters collapsing. This is usually accompanied by a check engine light being illuminated.
Use a stethoscope or a long screw driver and try to isolate where the knock is coming from.
If it's coming from a valve cover, remove the valve cover and you're likely to find a rocker laying around. If this is true you need to thoroughly inspect the valve train components.