There are more possibilities than the mind can imagine.Take it to a repair shop and have them inspect the underside. It could be the engine mounts, they might need replacing, check them first.
A bad harmonic balancer can cause a knocking noise. The harmonic balancer doesn't actually produce the noise, but it can cause the noise in the engine.
The guy in the trunk is still alive!!!
Replace the Harmonic balancer
A hole in the muffler would cause a knocking sound in your muffler. A loose exhaust pipe can also cause a knocking noise.
Power Steering?
sounds like a motor mount is broken or a transmition mount. have those checked.
Having a bad rod bearing could cause a truck to make a loud knocking noise and shake when driving at high speeds. The engine having a coolant leak or an engine timing problem could also cause the knocking noise.
can you elaborate? engine noise? stationary/moving? ticking, tapping or a definite knocking?
you may have a rod knocking and you need to take it to a shop asap
Typically, a knocking noise when to use your brakes in the car is caused by your brakes wearing down. This means you need to get them checked out and repaired.
A single knocking noise when braking or turning can be caused by a faulty axle. The cost of replacement is usually around 1,000 dollars.
Crank Shaft.